CH2056/TBR/ETBR
–
V.90 / 57,600bps/TBR21
CH1799/TBR/ETBR
–
V.34bis / 33,600bps/TBR21
CH1794
–
V.32bis / 14,400bps
FEATURES
The HS Modem family is pin compatible with
Supports V.90, V.34bis, V.34, V.32bis, V.32,
Cermetek’s low cost CH1786 V.22bis, 2400bps
V.22bis, V.22A/B, V.23, V.21, Bell 212A and 103.
modem family. Each module in the HS Modem family
is a self-contained modem and is FCC Part 68
CH2056 supports V.80 Synchronous operation.
approved
and
Canadian
DOT
approvable.
Error correcting: V.42 LAPM, MNP 2-4 and
Additionally,
the
CH1799TBR/ETBR
and
the
MNP10.
CH2056TBR/ETBR products meet the European
Data Compression: V.42bis and MNP 5
TBR21 requirements.
MNP10 Data through put enhancement for cellular
These ultra small modules are designed for PCB
operation.
through-hole mounting and are 1.35” x 1.38” x 0.55” in
DTE serial interface with speeds up to 230.4kbps
size. The HS Modem family requires only two external
(CH2056), 115.2 (CH1799) or 57.6kbps (CH1794).
interfaces: a ITU-T V.24 serial interface for direct
access to a UART, and a Tip and Ring RJ-11C Jack
Automatic baud rate adaptability utilizing speed
for the PSTN line connection. The HS Modem can be
sensing, flow control and data buffers.
controlled with industry standard AT commands and is
Send & Receive FAX class 1, Group 3 supported.
compatible with available industry communication
Serial V.24, 5 volt interface.
software.
NVRAM directory and stored profiles.
AT Command structure, with extensions.
DESCRIPTION OF FUNCTIONAL BLOCKS
Built-in DAA with 1500 VAC RMS isolation 2122V
AND DISCUSSION OF BASIC OPERATIONS
peak surge protection.
Figure 1 contains a functional block drawing of the HS
UL 1950 and CSA C22.2 950 Recognized
Modem family of products. Each HS Modem product
(E104957).
consists
of
a
serial
interface
buffer,
modulator/demodulator, modem controller with error
Leased Line version available CH1799LL
correction and data compression, non-volatile RAM
FCC part 68 Approved/DOT CSA CS-03 Part I
and a DAA.
Approvable.
+5 Volt operation with zero power option
Small size: 1.35” x 1.38” x 0.55”.
Pin compatible with low speed/low cost CH1786
TBR21
compliant
versions
available:
CH1799TBR/ETBR and CH2056TBR/ETBR.
INTRODUCTION
The CH2056, CH1799 and CH1794 (HS Modem
Family) are industrial grade high-speed modem
modules. Each HS Modem product supports a range
of modem standards and speeds from 300bps to
14,400bps, 28,800bps, 33,600bps or 57,600bps. By
using built in compression algorithms the operation
speed can be expanded to the maximum DTE rate of
Figure 1. Functional Block Diagram of HS Modem
57.6kbps for the CH1794, 115.2kbps for the CH1799
Family.
and 230.4kbps for the CH2056. A choice of error
correcting schemes is available including MNP 10 for
cellular telephone applications. The HS Modem family
Serial Host Interface Buffer. The HS Modem utilizes
supports Send and Receive FAX.
The CH1799LL
a serial V.24 EIA 232-E 5V interface to control the
operates exclusively on non-voltage bearing leased
modem. The HS Modem products can communicate
line.
over the serial interface with the Data Terminal
2004 Cermetek Microelectronics, Inc.
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Cermetek Microelectronics, Inc.
Equipment (DTE) at a fixed speed regardless of the
compliance, and also optionally for FCC Part 15
carrier line modulation speed (DCE) of the PSTN
compliance, these two pins must be routed through an
modem connection. This eliminates the need to have
external network such as that briefly described in
the DTE step up or step down in speed based on the
Figure 6A and described in more detail in Cermetek
in-coming or out-going PSTN communication data
Application Note # 126.
rate. Hence, the DTE can train the CH2056, to say
56kbps, and talk to a slower in-coming data
Each HS Modem product comes with FCC Part 68
connection at say, 2400bps without changing host
approval and is shipped from the factory with an FCC
speed. Conversely, the host DTE trained at 14.4kbps
Label indicating registration number and ringer
can also communicate with the modems at higher
equivalent. This label should be prominently displayed
speeds, say 28.8kbps.
This is accomplished by
on the end product. With the exception of the U.S.,
invoking internal automatic data flow control. The HS
most countries (including Canada) require submission
Modem family has a resident buffer to allow for this
of the final product or system containing the HS
auto baud operation.
Modem to the appropriate governing regulatory
agency for approval. Typically this is accomplished by
Non-Volatile RAM (NVRAM).
NVRAM can store
submitting the final end product to an independent test
user-customized
configurations.
The
AT&Wn
house or consultant for evaluation.
The test
command will store the active modem configuration in
house/consultant then forwards the test results and
one of two NVRAM locations as selected by an n of 0
applicable documents to the regulatory agency.
or 1. The AT&Yn command selects one of the stored
Contact Cermetek for a list of suggested consultants.
modem configurations to be automatically recalled and
made active upon reset or power up.
The ATZn
Modulation/Demodulation/Error
Correcting
and
command immediately recalls and activates a stored
Data Compression. These functions are provided by
configuration. See Tables 6A and 6B for storable S-
an industry standard modem chip set which has been
Registers and Commands.
adapted for use with the HS Modem family.
The
Modulation/Demodulation
scheme
supports
the
The NVRAM can save up to four telephone numbers,
industry modem standards listed below.
with up to 31 digits or modifiers in each telephone
number.
The AT&Zn=s command will store s, the
SUPPORTED MODULATION STANDARDS
telephone number dial string. The ATDS=n command
Bell 103
ITU-T V.22
will cause the modem to dial one of the four stored
Bell212A
ITU-T V.22bis
telephone numbers. The NVRAM storage location for
ITU-T V.32
the four telephone numbers is selected by an n of 0, 1,
ITU-T V.32bis
2, or 3.
ITU-T V.34
ITU-T V.34bis
Telephone Line Interface or DAA. High performance
ITU-T V.90
modems are extremely sensitive to DAA (Data Access
Arrangement) performance. The difference between a
The HS Modem supports V.42 LAPM, MNP 2-4, MNP
good modem and a fair one is in the DAA
10 error correcting protocols.
The CH1794 uses
performance.
The HS Modem family includes a
MNP5
data
compression
techniques
and
the
unique low distortion DAA designed for optimal
CH1799/CH2056 uses V.42bis data compression,
performance over all PSTN line conditions thereby
allowing data transmission rates of up to a maximum
achieving the most reliable and best performance
of
57.6kbps/115.2kbps/230.4kbps,
respectively.
PSTN connections.
These high DTE data rates are supported by the HS
Modem serial interface via its auto baud capability.
The HS Modem family is designed to meet North
Note that the maximum speed attained is limited by
American telephone standards as set by the FCC Part
the maximum speed available from the DTE.
68 (USA) and CSA CS-03 Part I (Canada). Among the
more critical parameters, the PSTN line interface is
The resident Modulator/Demodulator supports line
designed to meet 1500 VAC RMS isolation and
equalization and forward error correction.
provide 2122V peak surge protection. Consequently,
the HS Modem family of products satisfies U.S. and
Canadian
requirements,
and
will
meet
other
international
approval
agency
requirements
that
IMPORTANT NOTE
specify these levels of isolation.
The TBR/ETBR
The
V.90
standard
prescribes
56kbps
variants also meet the European TBR21 requirements.
downlink and 33.6kbps uplink. Consequently,
two V.90 modems connected back-to-back will
Pins 1 and 2 function as both input and output
send at 33.6kbps.
connections to the PSTN. To maximize field reliability
in hostile environments, for Canadian approval, for UL
2004 Cermetek Microelectronics, Inc.
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CONNECTING TO THE HOST UART
Modem is powered down. The internal blocking diode
Since a modem communicates data serially and most
provides supply isolation.
host products handle data in a parallel format, a UART
is needed to make parallel-to-serial and serial-to-
The pins of the HS Modem will be in an undefined
parallel translations.
state when powered is switched off.
This must be
taken into consideration to assure that no unwanted
signals are presented to the HS Modem during power
SUPPORTED FEATURES
down.
AT Command Set. The HS Modem supports the AT
Command set with extensions and can operate with
industry standard communication software. The AT
Commands are compatible with TR302.2/88-08006.
Serial Host Interface.
The HS Modem family
operates in asynchronous mode and supports a 5V,
RS232- like interface called V.24 (EIA-232-E). The HS
Modem supports a full RS-232C/V.24 serial interface.
Signal levels are TTL rather than RS-232C level
compatible, which allows direct connection of the HS
Modem to the host’s UART without level translating
circuitry.
See Table 3 for a complete set of pin
descriptions.
The modem is controlled by sending serial commands
over TXD and by monitoring serial status messages
returned on RXD. All other serial interface lines may
be utilized for the convenience of a particular
application but are not required by the modem.
Unused outputs from the HS Modem should be left
unconnected.
Unused inputs should be tied to the
Figure 2. Zero Power Operation.
proper logic level. See Table 3.
Power Supply. The HS Modem module is a complex
Speaker Interface.
The SPK output reflects the
set of sensitive subsystems.
During the course of
receiver analog input and provides a signal that can be
normal operation, the HS Modem decodes analog
used to monitor call progress. The SPK signal can
signals from the telephone line that are in the millivolt
drive a 300-ohm load directly.
Typically, the SPK
range. Steps must be taken by the user to guarantee
signal is input into an audio power amplifier and the
that power supply noise on all supply lines, including
amplifier, in turn, drives the speaker coil. The speaker
ground, does not exceed 25mV peak to peak.
If
is activated with the ATMn command. The speaker
necessary, use dedicated power and ground planes.
volume is adjusted using the ATLn command; where n
Failure to provide such operating conditions could
is 0, 1, 2, or 3. Increasing numbers correspond to
cause the HS Modem to malfunction or to function
higher volume.
Figure 3 indicates one method of
erratically.
driving an external 8-ohm speaker.
The HS Modem family requires +5V ±5% supply. It is
Zero Power Mode. If an application calls for zero
recommended that bypass capacitors be placed on the
power during standby periods, the power may be
power supply as close to the HS Modem’s supply input
switched off using external circuitry and then reapplied
pins as practical. It is recommended that a 10 µF or
when the HS Modem’s RI pin becomes active. The
greater tantalum capacitor in parallel with a 0.1 µF
HS Modem can thus be powered down to zero.
ceramic capacitor be used.
The user must also
provide shielding from nearby sources of EMI, such as
Referring to Figure 2, the controller activates the relay
relays, motors and other power supplies.
switch, supplying power (+5V) to the HS Modem. In
this configuration, the ring signal is used to “wake up”
Automatic Speed/Format Sensing. The HS Modem
the HS Modem when the HS Modem is in the power
supports both Command and Data modes of
down state.
operation.
The internal structure of the RI pin consists of an open
The HS Modem can automatically determine the
collector opto transistor with a 30k ohm pull-up through
speed and format of the data sent from the DTE over
a blocking diode to 5V. The user should apply his own
the serial interface; and can sense the following broad
pull-up resistor to an active 5V source when the HS
range of speeds:
2004 Cermetek Microelectronics, Inc.
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Document No. 607-0003 Revision K6 (08/04)
Cermetek Microelectronics, Inc.
CH1794
300, 600, 1200, 2400, 4800, 7200,
for an alternative voice/tone implementation that
9600, 12000, 14400, 19200, 38400, and
utilizes dual supply operational amplifiers.
57600bps.
CH1799
300, 600, 1200, 2400, 4800, 7200,
Table 2. HS Modem Auto Configuration Based on
9600, 12000, 14400, 16800, 19200,
DTE Configuration .
21600, 24000, 26400, 28800, 38400,
DTE Configuration
HS Modem
57600, and 115200bps.
Configuration
CH2056
300, 600, 1200, 2400, 4800, 7200,
7 mark
7 none
9600, 12000, 14400, 16800, 19200,
7 space
8 none
21600, 24000, 26400, 28800, 38400,
8 mark
8 none
57600, 115200, and 230400bps.
8 space
8 even
The data formats in Table 1 are recognized by the HS
Modem family of products.
Table 1. Data Formats Recognized by HS Modem
Family.
No. of
Character
Data Length
Stop
Length
Parity
(No. of Bits)
Bits
(No. of Bits)
None
7
2
10
Odd
7
1
10
Even
7
1
10
None
8
1
10
Odd
8
1
11*
Even
8
1
11*
*11 bit characters are sensed, but the parity bits are
Figure 3. Speaker Control Circuit.
stripped off during data transmission in Normal and
Error Correction modes.
All HS Modem products are designed with pin T1
The HS Modem can sense data with mark or space
coupled directly to the internal DAA. When using the
parity and configures itself as described in Table 2.
HS Modem in data mode, T1 should float and be
disconnected from any potential signal because any
The HS Modem is trained to a selected speed with an
signal on T1 during data operation will affect the HS
AT<CR> training sequence. Thus, the DTE to modem
Modem’s output. If T1 is being asserted from another
serial interface speed can be set independent of the
application, use a relay or zero impedance switch to
DCE or line carrier connecting speed (with minor
disconnect T1 when in data mode.
restrictions, see the AT+ MS command). This allows
greater flexibility when selecting DCE line carrier
When voice and data are both being used, and the T1
modulation speed thereby affording the user with
pin is active, it is typical for voice communication to
optimum data throughput performance. To maximize
precede data communication.
In this case, the
effective modem data throughput speed, the DTE to
following commands should be used to configure the
modem serial interface speed should be set to the
HS Modem to allow for full utilization of the Voice/Tone
highest speed available without invoking the use of the
injection feature.
These commands disable auto-
HS Modem’s built-in flow control.
Although flow
answer and eliminate hang-up due to lack of carrier
control facilitates communication with higher speed
signal.
modes by the DTE, use of flow control causes an
overall throughput data rate penalty.
1. Enter: ATS0=0<CR>
2. Enter: ATS7=255<CR>
Voice/Tone Injection Port. The HS Modem Family
3. Enter: ATS10=255<CR>
provides pin T1 to allow the user to share the PSTN
line interface associated with the modem for voice and
The
following
command
sequences
illustrate
DTMF applications.
Figure 5 contains a schematic
implementation
of
common
voice/tone
port
which uses a 5 Volt single supply operational amplifier
applications.
and indicates one possible configuration for voice/tone
utilization.
1. To answer a voice call:
(a) Enter: ATH1<CR>
Refer to Cermetek Application Note #170, 2-4 Wire
(b) Switch local voice source into T1
Converter for Use with CH179X and CH2056 Modems,
(c) Begin Voice Conversation
2004 Cermetek Microelectronics, Inc.
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Cermetek Microelectronics, Inc.
2. To switch to data mode, switch local voice source
The escape sequence consists of a “guard time” (a
from T1:
period where no characters are sent to the modem),
(a) At the Originate Modem, enter: ATX1<CR>
followed by 3 escape characters, followed by a second
(b) At the Answer Modem, enter: ATA<CR>
guard time. At power-up, the guard time is set to 1
second, and the escape character is set as ”+.” Note
3. To disconnect (hang-up) a voice call or data call:
that a 50 msec delay is required between escape
(a) Return to control mode by entering: +++
characters. These two parameters can be modified
(b) Enter: ATH<CR>
via registers S2 and S12, respectively.
4. To place a voice call using the HS Modem DTMF
The HS modem will stay off-hook with its carrier on
facilities:
after the escape sequence is received.
The HS
(a) Enter: ATDT1234567<CR>
Modem will return an OK status message when it is
Where 1234567 is the phone number
ready to accept commands. To put the HS Modem
(b) Then switch to local voice source
back into data mode, issue command ATO<CR> .
MODEM CONTROL
THE COMMAND FORMAT
The HS Modem may be controlled by sending serial
HS Modem commands consist of three elements:
ASCII command sequences. The commands are sent
1. The attention sequence,
to the modem serially on the TXD pin. After execution
2. The commands themselves and
of a received command, the modem returns a serial
3. A terminating carriage return.
status message that completion status. Refer to Table
5A, 5B and 5C for a complete list of status messages.
Enter:
ATDT1234567<CR>
Result:
Modem goes off-hook and tone dials phone
number 1234567.
MODEM STATES
The HS Modem can be in either command mode or
WARNING
data mode. When the modem is idle, it is in command
The HS Modem family of products has been FCC
mode by default and will recognize commands. When
Part 68 approved as data/FAX modems. Utilization
data transmission is in progress, the HS modem is in
of the Voice/Tone Port requires further registration.
the data mode state and will not recognize commands.
The FCC requires that the entire system, including
To force the HS Modem to recognize commands, the
the HS Modem and the handset or DTMF
host must send an “escape sequence” to the HS
transceiver, adhere to Part 68 rules.
Modem forcing it out of data mode and into command
mode.
TIP
RJ-11
ANALOG VOICE
T1
RING
JACK
INJECTED SIGNALS
SPK
SPEAKER
HS MODEM
CONTROL
FAMILY
RXD
NOTE: SPEAKER CONTROL AND PHONE
CONTROL ARE ANCILLARY CIRCUITS
V.24
DCD
SHOWN ELSEWHERE IN THIS DATA SHEET.
EIA-232-E
DSR
INTERFACE
* SIGNAL GND MUST BE CONNECTED TO
RI
EARTH GROUND
OR
CTS
UART
TXD
DTR
Vcc
Vcc
3
8
+
1
22K
RI
2
-
LM393
4
RST
LM393
4.7K
EXTERNAL RESET
10K
4.7uF
5
+
7
6
-
+5V
.1uF
Isolated
10K
GND
Envelope
Ring Detect
Figure 4.
HS Modem Family Application Diagram.
2004 Cermetek Microelectronics, Inc.
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Cermetek Microelectronics, Inc.
AT [Commands]<CR>.
Step 2. Initial Modem Training. The modem must be
Where: AT represents attention sequence. A and T
trained to the host DTE speed and parity (odd,
may be either upper or lower case but must be
even, mark, space or none). These activities
the same case.
[ Command ] represents
are briefly described below.
command strings.
HS Modem Reset. Upon applying power to the HS
Where: <CR> represents carriage return (ASCII 13 or
Modem, the HS Modem automatically generates an
HEX 0D)
internal reset pulse.
The user can also reset the
<LF> represents line feed (ASCII 10 or HEX
modem externally by applying a high-going reset pulse
0A)
to the RST pin for at least 10 msec after the +5V
power
supply
has
stabilized.
Delay
sending
The HS Modem will respond with one of the following
commands to the HS Mode for 2 seconds after reset
status messages depending on whether it is optioned
has been initiated to allow the HS Modem time to
for abbreviated (terse) or English (verbose) status
properly reconfigure.
messages.
On power up, or when reset is initiated either by the
Result: 0 <CR> (Terse)
ATZ<CR> command or by the RST pin, the modem
or
will reconfigure to its default state with the line carrier
Result: <CR><LF>
modulation speed set to:
OK
1. 14.4kbps for the CH1794
<CR><LF> (Verbose)
2. 33.6kbps for the CH1799
3. 57.6kbps for the CH2056
After accepting the AT<CR> command the HS modem
is in idle mode and is ready to accept additional
If desired, any speed, error correction, or data
commands.
compression method available on the HS Modem can
be locked in, using the AT\Nn and/or AT+MS
An alternate attention sequence A/ may be issued
commands.
which behaves much like the AT sequence except that
it causes the last entered command specified with an
Training the Modem. Each modem must be trained
AT prefix to be executed. When given, it must be in
to match the host DTE speed and parity so that it is
upper case ASCII. No carriage return is needed for
able to recognize serial asynchronous commands sent
this command.
to it by the DTE.
When entering commands to the modem, the
The DTE must retrain the modem each time a reset
backspace character-control-H (ASCII 8 or HEX 08)
pulse is applied on RST or after a RESET serial
can be used to edit mistakes. AT and A/ may not be
command has been issued.
edited however. Multiple commands may be placed
on a command line. A command line may be as long
as 40 characters, excluding the letters AT . By way of
STATUS MESSAGES AND RESULTS CODES
example, the command below instructs the HS Modem
A result code is issued by the HS Modem to the DTE
to configure itself to not echo characters when in
for all commands executed by the HS Modem except
command mode ( E0 ) and then puts itself in answer
dialing commands. Further, various activities on the
mode ( A ).
PSTN are also signaled to the DTE by the HS Modem.
All result codes have either a terse, short form version
Enter: ATE0A<CR>
(which is identified by a number followed by a <CR> )
Result: OK<CR><LF>
or a verbose long form English-like message version
(which is preceded and terminated with a <CR> and
AT Command Set. The available command set is
<LF> ).
divided into four types of commands: dial modifiers,
basic commands, ampersand and percent commands.
The user may suppress certain subsets of the non-
Refer to the complete list in Tables 6A and 6B.
extended result codes.
This is accomplished by
selecting subsets of the result code set using the
ATXn command, where n=0, 1, 2 or 3. Optionally, the
INITIALIZING THE MODEM
user may specify an extended set of results codes
Before commands may be sent to the HS Modem, the
(codes above 35) by setting Register S95. See the
modem must be initialized. This is a two step process:
detailed description of results codes in Table 5A, 5B
and 5C.
Step 1. Modem Reset.
This is accomplished by
applying a hardware-reset pulse to pin RST or
All AT commands, other than dialing commands, will
by switching the power off then back on.
be responded to with either an OK (short form result
2004 Cermetek Microelectronics, Inc.
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code 0) or the command is valid or accepted, or with
Application Note # 126.
Follow all applicable
an ERROR (result code 4) if the command is not
requirements for FCC Part 68 compliance. The User
recognized. The detail contained in the error result
is responsible to ensure that FCC Part 68 compliance
codes signaled to the DTE depends on the level of
is maintained.
message suppression employed by the user. As can
be seen from Tables 5A, 5B and 5C, specifying X4
As an alternative, the CH1799 will operate on a leased
allows the HS Modem to utilize the entire range of
line if the line is made wet by application of a DC
non-extended messages, whereas X0 suppresses all
voltage. Refer to Cermetek Application Note # 114 .
but the very basic result codes. Most of the result
codes allowed under X1, X2 and X3 are considered
WARNING
call progress status codes and, in practice, are
Operation of the CH1799LL on a standard PSTN
suppressed except for the case of debugging
line will damage the CH1799LL and void its
activities. It is recommended that the non-extended
warranty. Further, operation of the CH1799LL on a
result codes be used in all cases.
dry line without using proper current limiting circuitry
as outlined in Cermetek Application Note # 126 may
It should be noted that the default connect result codes
cause damage to the CH1799LL and will also void
9-20 indicate DTE connection speed, not Carrier Line
its warranty.
DCE speed.
Hence, a CH1794 will connect at a
maximum speed of 19.2kbps (result code 16). The
Table 4.
Pin Comparison of CH1786 and HS
CH1799 will connect at a maximum DTE speed of
Modem Family.
38.4kbps (result code of 17) and the CH2056 will
connect at a maximum speed of 57.6kbps (result code
PIN
CH1786
HS Modem Family
18) unless the DTE is forced to a higher speed by
1
RING
RING
selection of data compression.
In this case, the
2
TIP
TIP
maximum DTE to modem speed is 230.4kbps (result
3
RXA
T1
code20).
4
TXA
NC
Extensions to the basic result code set may be
5
SPK
SPK
specified by Register S95, which allows for the use of
6
NC
NC
result codes 40-64, 165-194.
7
NC
NC
IMPORTANT NOTE
8
SLEEP
OPEN*
Result codes 53-64 are supported by the CH1799
9
NC
NC
and CH2056.
Result codes 165-194 are only
10
TXD
TXD
supported by the CH2056. To obtain a detailed
11
RXD
RXD
status report for a given modem communication
configuration, use the AT\V1 command. Executing
12
V/D
OPEN*
this command at setup will cause the modem to
13
DTR
DTR
connect and return a message on line consisting of
14
DSR
DSR
<DTE speed> <modulation> <error protocol> <line
speed of connection>.
15
RI
RI
16
CTS (FX only)
CTS
17
DCD
DCD
LEASED LINE OPTION
18
HS
NC*
The CH1799LL is a leased line version of the CH1799.
Whereas the CH1799 requires an active voltage
19
V CC
V CC
bearing or wet PSTN line for normal operations
20
GND
GND
(typically, 48VDC on-hook line voltage), the CH1799LL
21
RST
RST
is designed to operate over a non-voltage bearing or
dry line.
22
NC
RTS
The CH1799LL will only operate properly on a dry line.
NOTES:
Damage will occur if used on a wet line.
The
1. * Indicates a difference between the CH1786 and
CH1799LL does not support ring detect but does
the HS Modem. The HS Modem may be directly
support
off-hook
control.
Refer
to
Cermetek
substituted for the CH1786 except in applications
Application Note # 116 for examples and instructions
where pins 3, 4, 8, 12, or 18 are used.
to establish a connection over a leased dry line wire
pair. Note that the length of the leased line is limited
2. NC signifies ‘No Connect.’
to 20,000 feet.
Use PSTN line protection as
recommended in Figure 6B and in Cermetek
2004 Cermetek Microelectronics, Inc.
Page 7
Document No. 607-0003 Revision K6 (08/04)
Cermetek Microelectronics, Inc.
Table 3.
HS Modem Family Pin Descriptions.
PIN
NAME
I/O
FUNCTION
1
RING
I/O
TELCO/TELSET INPUT . Directly connects to the telephone line’s RING lead through a
user supplied RJ-11C jack.
2
TIP
I/O
TELCO/TELSET INPUT . Directly connects to the telephone line’s TIP lead through a user
supplied RJ-11C jack.
3
T1
I/O
ANALOG VOICE INJECTED . Input (See Figure 5). 2.2V P-P max. Let float if not used.
4
NC
-
No connection.
5
SPK
O
SPEAKER . Audio output for speaker. See speaker control diagram.
6
NC
-
No connection.
7
NC
-
No connection.
8
NC
-
No connection.
9
NC
-
No connection.
10
TXD
I
TRANSMIT DATA .
Serial Transmit data input.
Marking, or a binary 1 condition, is
transmitted when a HIGH is asserted.
11
RXD
O
RECEIVE DATA . Serial Receive data output. Received marking or a binary 1 condition is
indicated by a HIGH.
12
NC
-
No connection.
13
DTR
I
DATA TERMINAL READY . Active LOW. Switching off DTR can either return modem to
command state, disconnect phone call, or reset the modem. DTR should be set LOW
when not used.
14
DSR
O
DATA SET READY . LOW indicates handshaking with a remote modem is in progress,
and/or the data carrier of a remote modem has been detected.
15
RI
O
RING INDICATION . This signal follows the frequency of the ringing signal and is normally
about 20 to 40 Hz for 2 seconds on with 4 seconds off.
16
CTS
O
CLEAR TO SEND . Active LOW. Indicates that the modem is ready to accept data from
the DTE.
17
DCD
O
DATA CARRIER DETECT . LOW indicates a data carrier from a remote modem has been
detected. This feature must be enabled using the &C1 command.
18
NC
-
No connection.
19
VCC
-
POWER SUPPLY . 5 Volts ± 5%. Note: Noise should be less than 25mV peak-to-peak.
20
GRD
-
GROUND . Note: Noise should be less than 25mV peak-to-peak.
21
RST
I
RESET . Active HIGH. This input must be asserted HIGH for at least 10-msec to reset the
modem. RESET is then returned to LOW for normal operation. If no system reset is
available, let this pin float to enable the internal reset.
22
RTS
I
REQUEST TO SEND . Active LOW. Used for flow control. Should be tied low if not used.
NOTE:
(1) If VCC has a slow power up ramp time, the internal reset may be ineffective.
(2) Do not drive LED’s directly from any output. Use Buffers.
2004 Cermetek Microelectronics, Inc.
Page 8
Document No. 607-0003 Revision K6 (08/04)
Cermetek Microelectronics, Inc.
AT COMMAND APPLICATIONS
Example:
Touch-tone dial 9, pause, go off-hook,
Dialing a Phone Number. The Dial command takes
return for additional AT commands.
the form Dn , where n is a string of characters. In the
Enter:
ATDT9, T;<CR>
simplest form, n will be only the digits of the phone
Result:
OK<CR><LF>
number to be dialed.
Automatic Answering.
Example:
Dial Number.
S0=0*
DO NOT ANSWER TELEPHONE
Enter:
ATD1234567<CR>
S0=1-254 ANSWER ON RING 1 TO RING 254
S0=255
ANSWER ON RING 255
In response to this command, the HS Modem dials the
telephone number “123-4567” and then waits for a
*When S0 is set to 0, the modem will not auto-answer.
carrier from the distant modem.
If no carrier is
detected within a given time (the default time is 30
seconds), the HS Modem automatically releases the
PHONE LINE CONNECTION GUIDELINES
line and sends a NO CARRIER result code.
If a
1.
The HS Modem must be mounted in the final
carrier is detected, the HS Modem gives a CONNECT
assembly such that it is isolated from exposure to
result
code
and
goes
on-line,
permitting
any hazardous voltages within the assembly.
communication with the distant modem.
Adequate separation and restraint of cables and
cords must be provided.
The Dial command may also be issued without a
telephone number. ATD causes the modem to pick up
2.
The circuitry from the HS Modem to the
the telephone a line without dialing a number.
telephone line interface must be provided in
wiring that carries no other circuitry other than
Pause During Dialing. When placing a call from an
that specifically allowed in the FCC rules (such as
office with a telephone connected to a PBX, it may be
A and A1 leads).
necessary to dial an access code (usually the digit 9)
to get an outside line.
Inserting a comma in the
3.
Connection to phone line should be made
telephone number commands the modem to pause for
through an RJ-11C jack.
a specific length of time. The factory default pause
time is 2 seconds.
4.
PCB traces from the modem’s RING and TIP pins
to the RJ-11C jack must be 0.1 inch spacing or
Example:
Dial 9, pause, dial number.
greater to one another and 0.2 inch spacing or
Enter:
ATDT9, T1234567<CR>
greater to all other traces.
The traces should
Result:
OK<CR><LF>
have a nominal width of 0.020 inches or greater.
Multiple commas may be used for a greater delay
5.
The RING and TIP PCB traces should be as
time.
short as possible and oriented to prevent
coupling other high speed or high frequency
Touch Tone and Pulse Dialing. The modem can use
signals present on the host circuit PCB.
DTMF (touch-tones) T , or dial pulses P when dialing a
telephone number.
If the dial command does not
6.
No additional circuitry other than that shown in
specify which type to use, the modem defaults to the
Figure 7 may be connected between the modem
type last specified. The power-on default value is T .
module and the RJ-11C jack.
Doing so will
invalidate the FCC approval.
Example:
Pulse dial 9, pause, touch-tone dial
number.
7.
The HS Modem, the RJ-11C jack, the interfacing
Enter:
ATDP9, T1234567<CR>
circuitry and all PCB traces in between, must be
Result:
OK<CR><LF>
contained on a PCB with a 94 V-0 flammability
rating.
Redial Last Number. Use A/ , the repeat command,
to redial the last telephone number dialed when a busy
8.
The supplied FCC registration label must be
signal is received.
applied visibly on the outside of the product.
Go Off-Hook and Return to Command State. The
9.
The product’s User Manual must provide the user
modem can be forced to reenter the command state
with instructions for connection and use as
after going off-hook by issuing the ATDT command
recommended in the FCC Registration Section
with a semi-colon.
This is useful when using the
below.
modem with an independent DTMF tone generator.
2004 Cermetek Microelectronics, Inc.
Page 9
Document No. 607-0003 Revision K6 (08/04)
Cermetek Microelectronics, Inc.
CANADIAN APPROVALS
In addition to restriction notification, the FCC requires
The HS Modem family is approvable for use by DOT to
that Cermetek make all repairs to all products in the
CSA CS-03 Part I.
However, per Canadian
HS Modem family.
If repairs are necessary after
procedures, approval can only be granted after the HS
installation of the HS Modem and the end product has
Modem has been installed into the end product.
been delivered to the end user, the end product must
Typically, Canadian approval is obtained by submitting
be returned to the end product supplier where the HS
the final end product to an independent test house or
Modem can be removed and then forwarded to
consultant for evaluation. The test house/consultant
Cermetek for repair.
The following notice is
then
forwards
the
test
results
and
applicable
recommended and should be included in the end
documents to the regulatory agency. Cermetek offers
product’s user manual.
a list of consultants to assist with this process.
FOR YOUR USER’S MANUAL
PAN-EUROPEAN TBR21 APPROVALS
The Part 68 rules require the following (or equivalent)
The
CH1799TBR/ETBR
and
CH2056TBR/ETBR
be provided to the end user of the equipment
products
have
been
designed
to
meet
the
containing a DAA:
requirements of ETSI TBR – 021 Pan-European
Approval for Connection to Analogue Public Switched
Type of Service. The (insert end product name) is
Telephone Networks in addition to the FCC Part 68
designed to be used on standard device telephone
conveyed approval, Canadian DOT CSA CS-03 Part I
lines. It connects to the telephone line by means of a
compliance and UL 1950 Edition 3/CSA C22.2 950
standard jack called the USOC RJ-11C (or USOC
recognition. Test reports (as required for CE marking)
RJ45S). Connection to telephone-company-provided
demonstrating TBR21 compliance are available upon
coin service (central office implemented systems) is
request.
prohibited. Connection to party lines service is subject
to state tariffs.
HS MODEM HANDLING AND ASSEMBLY
Changes in Attestation Procedure for Plugs and
RECOMMENDATIONS
Jacks. (Name of applicant) attests that the network
The HS Modem contains static-sensitive components
interface plugs or jacks used on this equipment comply
and should only be handled by personnel and in areas
with and will continue to comply with the mechanical
that are properly protected against static discharge.
requirements specified in Part 68, Sub-part F,
specifically the dimensions, tolerances and metallic
There
are
two
mounting
techniques
that
are
plating requirements.
The compliance of these
recommended for physically connecting the HS
connectors will be assured by purchase specifications
Modem to a PCB:
and incoming inspection.
Documentation of such
1. Direct soldering.
specifications and/or inspections will be provided by
2. Sockets.
the FCC within 30 days of their request for the same.
Direct Soldering.
The HS Modem may be wave
Telephone Company Procedure. The goal of the
soldered onto a circuit card. All HS Modem products
telephone company is to provide you with the best
are hermetically sealed and will not be harmed by
service it can. In order to do this, it may occasionally
industry standard wave soldering processes.
be necessary for them to make changes in their
equipment, operations or procedures.
If these
Socketing.
The socketing approach to mounting
changes might effect your service or the operation of
eliminates cleaning and desoldering concerns. When
your equipment, the telephone company will give you
the socket is used, it must make a solid connection to
notice, in writing, to allow you to make any changes
all pins.
Failure to do so will cause unreliable or
necessary to maintain uninterrupted service.
intermittent operation. Also, steps should be taken to
assure that the module remains tightly seated in the
In certain circumstances, it may be necessary for the
socket after the end product is shipped. Cermetek
telephone company to request information from you
recommends socket CES-150-01-T-S by Samtec, 50
concerning the equipment which you have connected
pin strip socket.
to your telephone line. Upon request of the telephone
company, provide the FCC registration number and
the ringer equivalence number (REN); both of these
FCC REGISTRATION
items are listed on the equipment label. The sum of all
All products in the HS Modem family are registered
of the REN’s on your telephone lines should be less
with the FCC (except the CH1799LL) under Part 68.
than five in order to assure proper service from the
To maintain the validity of the registration, you must
telephone company. In some cases a sum of five may
serve notice to the end user of the product of several
not be useable on a given line.
Consult your
restrictions the FCC places on the modem and its use.
telephone provider.
2004 Cermetek Microelectronics, Inc.
Page 10
Document No. 607-0003 Revision K6 (08/04)
Cermetek Microelectronics, Inc.
If Problems Arise.
If any of your telephone
Flash to on hook = 70 msec
equipment is not operating properly, you should
Auto speed detection enabled
immediately remove it from you telephone line, as it
DTE connect speed, connect messages
may cause harm to the telephone network.
If the
Back space character = 08 (BS) Carriage return
telephone company notes a problem, they may
character = 13 (CR)
temporarily discontinue service. When practical, they
Line feed Character = 10 (LF)
will notify you in advance of this disconnection.
If
Duration of wait for dial tone =2 seconds
advance notice is not feasible, you will be notified as
Duration of wait for carrier after dialing = 50 seconds
soon as possible.
Carrier detect response time = 0.6 seconds
Escape code guard time = 1 second
When you are notified, you will be given the
Length of use after comma = 2.0 seconds
opportunity to connect the problem and informed of
Last carrier to hang up delay = 1.4 seconds
your right to file a complaint with the FCC. Contact
DTMF interdigit delay = .095 seconds
your local telephone service provider if you have any
Auto sync address or address detection =0
questions about your phone. Line.
Connection detected at DTE – Highest speed
38,400kbps
In the event repairs are ever needed on the (insert
Auto retrain enabled – 30 seconds attempts
your product name), they should be performed by
MNP error correction mode can be negotiated (&Q5)
(insert your company name), or an authorized
MNP – non-extended service selected
representative or (insert your company name).
For
MNP error correction block size is 128 characters
information contact: (insert your company address).
selected
Data compression – negotiation enabled
Transmit break length is 0.3 seconds
DEFAULT STATUS, PERFORMANCE AND
All breaks are transmitted in sequence with data
SPECS
Serial port flow control enabled = RTS/CTS
Prior to delivery, Cermetek installs into each HS
XON/XOFF flow control characters selected
Modem the following default Configuration Profile:
IMPORTANT NOTE
Default Connect Speeds are 14,400bps, 33,600bps
Upon power-up the HS Modem will recall user profile
and 57,600bps for CH1794, CH1799 and CH2056
0 which may override some of the above Factory
respectively
Defaults.
If desired the user may, at their option,
Serial port data rate auto baud enabled
save the factory defaults in user profile 0.
Bell 212A operation at 1200bps
Parity – none
Table 5A. Summary
of
Non-Extended
Result
Auto answer disabled
Codes.
Command echo ON
Result Code Form
n is ATXn
All result codes enabled – except \REL codes
Command
Wait for dial tone before dialing – 2 seconds
Terse
Verbose or Long
0
1
2
3
4
Dials with touch-tone (T)
or
Detects busy signal (ATX4)
Short
Full word result codes – non-extended
0
OK
X
X
X X
X
Pulse dial make/break ratio = 39/61-10pps
1
CONNECT
X
X
X X
X
Test timer set to 0 seconds, test modes disabled
2
RING
X
X
X X
X
Inactivity timer set to 0 minutes
CTS always active
3
NO CARRIER
X
X
X X
X
DSR is ignored
4
ERROR
X
X
X X
X
DCD is ignored
5
CONNECT 1200
1
X
X X
X
RTS to CTS delay - .01 seconds
6
NO DIAL TONE
3
3
X X
X
DTR always active – hang up after transition
7
BUSY
3
3
3
X
X
Long space disconnect disabled
8
NO ANSWER
X
X
X X
X
Speaker enabled but off when receiving carrier
9
CONNECT 0600
1
X
X X
X
Speaker volume set to low
10
CONNECT 2400
1
X
X X
X
Local modem will not grant RDL request from remote
11
CONNECT 4800
1
X
X X
X
modem
12
CONNECT 9600
1
X
X X
X
Guard tones disabled
13
CONNECT 7200
1
X
X X
X
Minimum DTR pulse width = .05 seconds
14
CONNECT 12000
1
X
X X
X
Ring count – 00
15
CONNECT 14400
1
X
X X
X
Escape code character = 43 (+)
16
CONNECT 19200
1
X
X X
X
2004 Cermetek Microelectronics, Inc.
Page 11
Document No. 607-0003 Revision K6 (08/04)
Cermetek Microelectronics, Inc.
Figure 5. Schematic Illustrating Implementation of Voice Injection Feature.
Table 5A. Summary
of
Non-Extended
Result
Table 5B. CH1799
Extended
Result
Codes
Codes (Continuation).
(Continuation).
Result Code Form
n is ATXn
Result Code Form
n is ATXn
Command
Command
Terse
Verbose or Long
0
1
2
3
4
Terse
Verbose or Long
0
1
2
3
4
or
or
Short
Short
17
CONNECT 38400
1
X
X X
X
58
+MRR: 28800
X
X
X
X
X
18
CONNECT 57600
1
X
X X
X
59
CARRIER 16800
1
X
X
X
X
19
CONNECT 115200
1
X
X X
X
61
CARRIER 21600
1
X
X
X
X
20
CONNECT 230400
X
X
X X
X
62
CARRIER 24000
1
X
X
X
X
22
CONNECT
1
X
X X
X
63
CARRIER 26400
1
X
X
X
X
75TX/1200RX
64
CARRIER 28800
1
X
X
X
X
23
CONNECT
1
X
X X
X
66
+DR: ALT
X
X
X
X
X
1200TX/75RX
67
+DR: V42B
X
X
X
X
X
24
DELAYED
4
4
4
4
X
69
+DR: None
X
X
X
X
X
32
BLACKLISTED
4
4
4
4
X
70
+ER: NONE
X
X
X
X
X
33
FAX
X
X
X X
X
77
+ER: LAPM
X
X
X
X
X
35
DATA
X
X
X X
X
80
+ER: ALT
X
X
X
X
X
84
CONNECT 33600
1
X
X
X
X
Table 5B. CH1799 Extended Result Codes.
91
CONNECT 31200
1
X
X
X
X
Result Code Form
n is ATXn
Command
IMPORTANT NOTE
Terse
Verbose or Long
0
1
2
3
4
This note applies to Tables 5A, 5B, and 5C. An
or
“X” in a column indicates that the message (either
Short
the long form if verbose, or the value only for short
40
+MRR: 300
X
X
X
X
X
form) will be generated when that particular value
44
+MRR: 1200/75
X
X
X
X
X
of “n” (shown at the top of the column) has been
45
+MRR: 75/1200
X
X
X
X
X
selected by the use of ATXn . A numeral indicates
46
+MRR: 1200
X
X
X
X
X
which less explicit message (verbose or short
47
+MRR: 2400
X
X
X
X
X
form) will be output for that X option.
48
+MRR: 4800
X
X
X
X
X
49
+MRR: 7200
X
X
X
X
X
Table 5C. CH2056 Extended Result Codes.
50
+MRR: 9600
X
X
X
X
X
Result Code Form
n is ATXn
51
+MRR: 12000
X
X
X
X
X
Command
52
+MRR: 14400
X
X
X
X
X
Terse
Verbose or Long
0
1
2
3
4
53
+MRR: 16800
X
X
X
X
X
or
54
+MRR: 19200
X
X
X
X
X
Short
55
+MRR: 21600
X
X
X
X
X
165
CONNECT 32000
X X X X X
56
+MRR: 24000
X
X
X
X
X
166
CONNECT 34000
X X X X X
57
+MRR: 26400
X
X
X
X
X
167
CONNECT 36000
X X X X X
2004 Cermetek Microelectronics, Inc.
Page 12
Document No. 607-0003 Revision K6 (08/04)
Cermetek Microelectronics, Inc.
Table 5C. CH2056
Extended
Result
Codes
Table 6A. Summary of Basic AT Commands
(Continuation).
(Continuation).
Result Code Form
n is ATXn
Command
Function
Command
H, H0
Initiate a hang-up sequence
Terse
Verbose or Long
0
1
2
3
4
H1
If on-hook, go off-hook and enter
or
command mode
Short
L0
Set low speaker volume
168
CONNECT 38000
X
X
X
X
X
L1
Set low speaker volume
169
CONNECT 40000
X
X
X
X
X
L2
Set medium speaker volume
170
CONNECT 42000
X
X
X
X
X
L3
Set high speaker volume
171
CONNECT 44000
X
X
X
X
X
M0
Speaker off
172
CONNECT 46000
X
X
X
X
X
M1
Speaker on during hand shaking and
173
CONNECT 48000
X
X
X
X
X
speaker off while receiving carrier
174
CONNECT 50000
X
X
X
X
X
M2
Speaker on during hand shaking and
175
CONNECT 52000
X
X
X
X
X
while receiving carrier
176
CONNECT 54000
X
X
X
X
X
M3
Speaker
off
during
dialing
and
177
CONNECT 56000
X
X
X
X
X
receiving Carrier and speaker on
178
CONNECT 23040
X
X
X
X
X
during answering
180
CONNECT 28000
X
X
X
X
X
O0
Go on-line
181
CONNECT 29333
X
X
X
X
X
O1
Go on-line and initiate a retrain
182
CONNECT 30667
X
X
X
X
X
sequence
183
CONNECT 33333
X
X
X
X
X
Q0
Allow result codes to DTE
184
CONNECT 34667
X
X
X
X
X
Q1
Inhibit result codes to DTE
185
CONNECT 37333
X
X
X
X
X
Sn
Select S-Register as default
186
CONNECT 38667
X
X
X
X
X
Sn?
Return the value of S-Register n
187
CONNECT 41333
X
X
X
X
X
Sn=v
Set S-Register n to value (v)
188
CONNECT 42667
X
X
X
X
X
V0
Report short form (terse) result codes
189
CONNECT 45333
X
X
X
X
X
V1
Report long form (verbose) result
190
CONNECT 46667
X
X
X
X
X
codes
191
CONNECT 49333
X
X
X
X
X
W0
Report DTE speed
192
CONNECT 50677
X
X
X
X
X
W1
Report line speed, EC protocol and
193
CONNECT 53333
X
X
X
X
X
DTE speed
194
CONNECT 54377
X
X
X
X
X
W2
Report DCE speed
X0 to X4
Report basic call progress result
Table 6A. Summary of Basic AT Commands.
codes, i.e. OK, CONNECT<RING,
Command Function
NOCARRIER
(also
for
busy,
if
A/
Re-execute command
enabled, and dial tone not detected),
A
Go off-hook and attempt to answer call
NO ANSWER and ERROR
B0
Select CCITT connection at 300 or
Z0, Z1
Initiate modem soft reset.
Restore
1200bps
stored profile 0 or 1 after reset
B1
Sect Bell connection at 300 or 1200bps
&C0, &C1
Force DCD active regardless of the
Dn
Dial modifier
carrier state or allow DCD to follow the
P
Pulse Dial
carrier state
T
Touch Tone Dial
&D0
Modem ignores DTR. (Default)
W
Wait for Dial Tone
&D1
Modem assumes command state
;
Return to Command State
&D2
Modem hangs up, assumes command
@
Wait for Quiet Answer Command
state and disables auto-answer
!
Flash Hook
&D3
Modem assumes initialization state
,
Pause
&F0
Restore Factory configuration 0
0-9/ABCD Dial Digits/Characters & wait
&F1
Restore Factory configuration 1
for credit card dial tone
&K0
Disable DTE/DCE flow control
^
Toggles calling tone
&K1,2
Not Supported
L
Redial last number
&K3
Enable
RTS/CTS
DTE/DCE
flow
*,#
Star digit – tone dialing
control
S=n
Dial the number and store in
&K4
Enable XON/XOFF DTE/DCE flow
Directory, n= 0 to 3
control
E0
Enable command echo
&K5
Enable transparent XON/XOFF flow
E1
Disable command echo
control
2004 Cermetek Microelectronics, Inc.
Page 13
Document No. 607-0003 Revision K6 (08/04)
Cermetek Microelectronics, Inc.
Table 6B. Summary of Basic AT Commands.
Command
Function
Command
Function
&Q6
Select
asynchronous
operation
in
OPERTING MODE COMMANDS
normal mode
\N0
Select normal speed buffered mode
&V
Display current configuration
\N1
Select direct mode
&W0
Store the active profile in NVRAM
\N2
Select reliable mode
profile 0
\N3
Select auto reliable mode
&W1
Store the active profile in NVRAM
\N4
Force LAPM mode
profile 1
\N5
Force MNP mode
&Y0
Recall stored profile 0 upon power up
\V0
Connect messages are controlled by
&Y1
Recall stored profile 1 upon power up
the command settings X, W, and S95
&Zn=x
Store dial string x (31 digits max) to
\V1
Connect messages are displayed in
location n (0-3)
the single line format
MNP10 COMMANDS
+MS
Select modulation
-K0
Disable MNP 10 extended services
ERROR CORRECTING COMMANDS
-K1
Disable MNP 10 extended services
%C0
Disable data compression
-K2
Disable MNP 10 extended services
%C1
Enable MNP 5 data compression
FAX CLASS 1
%C2
Enable V.42bis data compression
+FCLASS=n
Service Class (n=0 to 3)
%C3
Enable both V.42bis and MNP 5
IDENTIFICATION COMMANDS
compression
I0
Reports product code
\Bn
Send break of n x 100 msec (n=0 to 9)
I3
Reports firmware Identification code
&R0
CTS tracks RTS
&R1
CTS always on
&S0
DSR always on
&S1
DSR active after answer tone detected
and inactive after loss of carrier
&Q0
Select direct asynchronous mode
&Q5
Modem negotiates an error corrected
link
2004 Cermetek Microelectronics, Inc.
Page 14
Document No. 607-0003 Revision K6 (08/04)
Cermetek Microelectronics, Inc.
Table 7. S-Register Summary.
Firmware
Factory
Register
Function
Range
Units
Saved
Defaults
Defaults
S0
Rings to Auto-Answer
0-255
rings
*
000
000
S1
Ring Counter
0-255
rings
000
000
S2
Escape Character
0-255
ASCII
*
043
043
S3
Carriage Return Character
0-127
ASCII
013
013
S4
Line Feed Character
0-127
ASCII
010
010
S5
Backspace Character
0-255
ASCII
008
008
S6
Wait Time before Dial Tone or Blind Dialing
2-255
s
*
002
002
S7
Wait Time for Carrier, Silence or Dial Tone
1-255
s
*
050
050
S8
Pause Time for Dial Delay Modifier
0-255
s
*
002
002
S9
Carrier Detect Response Time
1-255
0.1s
*
006
006
S10
Carrier Loss Disconnect Delay
1-255
0.1s
*
014
014
S11
DTMF Tone Duration
-
-
095
095
S12
Escape Prompt Delay
0-255
0.02s
*
050
050
S13
Reserved
-
-
000
000
S14
General Bit Mapped Options Status
-
-
*
138 (8AH)
138 (8AH)
S15
Reserved
-
-
000
000
S16
Test Mode Bit Mapped Options Status (&T)
-
-
000
000
S17
POS Option
-
-
000
000
S19
Reserved
-
-
000
000
S20
Reserved
-
-
000
000
S21
V.24/General Bit Mapped Options Status
-
-
*
052 (34H)
020 (14H)
S22
Speaker/Results Bit Mapped Options Status
-
-
*
117 (75H)
117 (75H)
S23
General Bit Mapped Options Status
-
*
000
000
S24
Sleep Inactivity Timer
0-255
s
*
000
000
S25
Delay to DTR off
0-255
s or 0.01s
005
005
S26
RTS-to-CTS Delay
0-255
0.01s
001
001
S27
General Bit Mapped Options Status
-
-
*
073 (49H)
073 (49H)
S28
General Bit Mapped Options Status
-
-
*
000
000
S29
Flash Dial Modifier
0-255
0.01s
070
070
S30
Disconnect Inactivity Timer
0-255
10s
000
000
S31
General Bit Mapped Options Status
-
-
*
192 (C0H)
192 (C0H)
S36
LAPM Failure Control
-
-
*
007
007
S37
Line Connection Speed
-
-
*
000
000
S38
Delay Before Forced Hang-up
0-255
s
020
020
S39
Flow Control Bit Mapped Options Status
-
-
*
003
003
S40
General Bit Mapped Options Status
-
-
*
104 (68H)
104 (68H)
S41
General Bit Mapped Options Status
-
-
*
195 (C3H)
195 (C3H)
S43-S45
Reserved
-
-
-
-
S46
Data Compression Control
-
-
*
138
138
S48
V.42 Negotiation Control
-
-
*
007
007
S82
LAPM Break Control
-
-
000
000
S86
Call Failure Indeification
0-26
-
021
021
S91
PSTN Transmit Attenuation Level
0-15
dBm
10
10
S92
FAX Transmit Attenuation Level
0-15
dBm
10
10
S95
Result Code Messages Control
-
-
*
000
000
S210
V.34 Symbol Rate
0-255
-
13 (0DH)
13 (0DH)
NOTES:
1. Parameters indicated with a (*) in the Saved column may be stored in User Profile n=0, 1 by executing
the appropriate &Wn command.
2. A stored Profile is a subset of allowed parameters and is comprised of those parameters displayed
with the &V command.
3. Factory Default values that are different from the Firmware Default values are highlighted in BOLD .
4. Restore Factory Default values using Zn command.
5. Restore Firmware Default values using &Fn command.
2004 Cermetek Microelectronics, Inc.
Page 15
Document No. 607-0003 Revision K6 (08/04)
Cermetek Microelectronics, Inc.
Figure 6. PSTN Line Interface for all HS Modems.
1. Currently Limiting
PSTN
Protection
Line
some form of surge protection as described herein
Device.
to maintain conveyed FCC Part 68 approval.
Currently limiting devices are mandatory to meet
Refer to Application Note # 130 for a list of
UL safety standards. To maintain conveyed FCC
recommended suppliers.
Part 68 approval, the current limiting components
identified as F1 and F2 in dashed Box #1 must
4. Optional External Over Voltage and Lightning
also survive FCC Part 68 surge testing. Refer to
Protection.
Cermetek Application Note #126, Supplemental
In most environments, the internal two terminal
PSTN Line Protection, for more details. Refer to
surge suppressor (see dashed Box 3) is adequate.
Application Note # 130, Summary of Recommend
For severe environments, use an external three
Suppliers, for a list of suppliers and associated
terminal device with an earth ground as is shown
part numbers.
in dashed Box 4.
A resettable/repairable fuse (rated at 0.15 amps)
5. EMI/RFI Suppression.
is preferred because it resets automatically upon
EMI/RFI suppression is recommended. This is for
removal of the current flow.
Non-resettable
obtaining FCC part 15 A and/or B. It is also used
devices are also acceptable. Although CS-03 Part
to suppress external EMI / RFI signals that can
1 (Canada) follows the requirements of FCC Part
affect modem operation, such as strong radio
68 (USA), Cermetek recommends contacting a
signals, should the modem be near a source of
certified independent lab to verify compliance in
such signals.
No external EMI/RFI noise
the specific application.
suppression circuitry is required to maintain
conveyed FCC Part 68 approval.
Additional
2. PSTN Current Limiting Resistors.
suppression may be added as described below
Low value (10 Ω ) carbon film 1/4 watt resistors may
without adversely affecting FCC Part 68 approval.
be required (identified as R1 and R2 in dashed
Box 2), depending on end product application
A. To provide adequate EMI/RFI suppression,
environment, to enhance performance by reducing
the capacitor/inductor network contained in
susceptibility to PSTN current surges that may
dashed Box 5 should be located as close to
occur before the OVERVOLTAGE PROTECTION
the RJ-11C Jack as possible.
Further, this
device (identified as D1 in dashed Box 3)
network should be provided with an excellent
becomes fully activated.
ground path to the chassis.
Refer to Cermetek Application Note # 130,
B. Capacitors C1 and C2 should not exceed
Summary of Recommended Supplies, for a list of
0.005 µ f. They must have a rating of 1.5KV
suppliers.
and typically are 0.001 µ f ± 20%. Inductors L1
and L2 may be either individual inductors or a
3. Over Voltage and Lightning Protection.
dual inductor. Refer to Application Note #130
Surge Protection is provided by internal circuitry
for a complete list of recommended vendors
contained within all HS modems. No additional
and associated part numbers.
For UL
external components are required to maintain
applications, choose capacitors and inductors
conveyed FCC Part 68 approval for all HS
that are UL 1950 Edition 3 listed. The actual
modems (excluding the CH1799ALL).
values of the components used may vary
depending on the end product design and the
For CH1799ALL, the required surge protection
nature of the EMI/ RFI. Consult an FCC part
(identified as D1 in dashed Box 2) must be
15 consultant if required.
supplied externally. The purchaser must include
2004 Cermetek Microelectronics, Inc.
Page 16
Document No. 607-0003 Revision K6 (08/04)
Cermetek Microelectronics, Inc.
Table 8. HS Modem Electrical Specifications.
Symbol
Characteristic
Min.
Typ.
Max.
Units
V CC
Positive Supply Voltage
4.5
5.0
5.5
V
I CC Off Hook
Operating Current @
175
mA
V CC = 5.5V when modem is Off Hook
I CC On Hook
Operating Current @
170
mA
V CC = 5.5V when modem is Off Hook
V IH
High Level Input Voltage*
2.0
V
V IL
Low Level Input Voltage*
0.8
V
VT+
Positive Hysteresis Threshold for RESET Pin
2.5
V
VT-
Negative Hysteresis Threshold for RESET Pin
0.5
V
V OH
High Level Output (I OH = 0.5 mA)*
2.4
V
V OL
Low Level Output (I OL = 1.6 mA)*
0.6
V
I IN
Input Leakage Current (TXD, DTR, RTS)
100
µ A
I OH
Input Current (RST)
500
µ A
C p
Capacitive Load (TXD, DTR, RTS)
10
pF
Capacitive Load (RST)
8
pF
Test conditions: VCC = 5V ± 10%, Temp = 0°C to 70°F (unless otherwise stated).
*Output Load = 50 pF ± one TTL.
Table 9. HS Modem Electrical Specifications.
Parameter
Min.
Typ.
Max.
Units
Comments
Off Hook Impedance
20
Ohm
Trans Hybrid Loss
25
dB
600 Ohm, RXA, TXA
Ring Voltage Loop
110V
250V
V PP
On 48VDC line voltage for sustained
periods
Line Loop Current – (Off
20
100
mA
Does not apply to CH1799LL
Hook)
Return loss @ 1000 Hz
15
dB
600 Ohm
Ring Frequencies
40
Hz
Receiver Insertion Gain
-0.5
0.0
+0.5
dB
Transmit Power
-9.5
dBm
600 Ohm – Data Mode
First Character After Reset
1.0
sec
Delay
Inter Character Delay
20
50
msec
Between all command characters
Command Delay
100
200
msec
Between all AT command characters*
Minimum Reset Pulse
10
msec
If user supplied
Duration
* Note: Must wait for modem response before issuing new command.
2004 Cermetek Microelectronics, Inc.
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Document No. 607-0003 Revision K6 (08/04)
Cermetek Microelectronics, Inc.
Table 10. Analog Characteristics.
Name
Type
Characteristic
Value
SPK
O(DF)
Minimum Load
300 Ohms
Maximum Capacitive Load
0.01µf
Output Impedance
10 Ohms
Output Voltage
2.5 ± 1.6V
D.C. Offset
<20mV
Table 11. Summary HS Modem Family of Products.
Model
Summary of Features
Operating Temperature
CH1794
Full Function, 14.4kbps, FCC Part 68 Approved, UL 1950
0°C to + 70°C
Listed
CH1794ET
Full Function, 14.4kbps, FCC Part 68 Approved, UL 1950
-40°C to +85°C
Listed
CH1799
Full Function, 33.6kbps, FCC Part 68 Approved, UL 1950
0°C to + 70°C
Listed
CH1799ET
Full Function, 33.6kbps, FCC Part 68 Approved, UL 1950
-40°C to +85°C
Listed
CH1799LL
Full Function, 33.6kbps, FCC Part 68 Approved, UL 1950
0°C to + 70°C
Listed
CH1799TBR
Full Function, 33.6kbps, FCC Part 68 Approved, UL 1950
0°C to + 70°C
Listed,
TBR21 Compliant
CH1799ETBR
Full Function, 33.6kbps, FCC Part 68 Approved, UL 1950
-40°C to +85°C
Listed,
TBR21 Compliant
CH2056
Full Function, 56.0kbps, FCC Part 68 Approved, UL 1950
0°C to + 70°C
Listed
CH2056ET
Full Function, 56.0kbps, FCC Part 68 Approved, UL 1950
-40°C to +85°C
Listed
CH2056TBR
Full Function, 56.0kbps, FCC Part 68 Approved, UL 1950
0°C to + 70°C
Listed,
TBR21 Compliant
CH2056ETBR
Full Function, 56.0kbps, FCC Part 68 Approved, UL 1950
-40°C to +85°C
Listed,
TBR21 Compliant
2004 Cermetek Microelectronics, Inc.
Page 18
Document No. 607-0003 Revision K6 (08/04)
Cermetek Microelectronics, Inc.
Table 12. HS Modem Family Pin Functions.
PACKAGE CONNECTION TABLE
PIN NO.
FUNCTION
PIN NO.
FUNCTION
1
RING
12
NC
2
TIP
13
DTR
3
T1
14
DSR
4
NC
15
RI
5
SPK
16
CTS
6
NC
17
DCD
7
NC
18
NC
8
NC
19
VCC
9
NC
20
GND
10
TXD
21
RST
11
RXD
22
RTS
NOTES:
1. All dimensions are inches.
2. Case dimensions are nominal ± 0.02 inches.
3. Pin length is nominal ± 0.03 inches.
4. Pin dimensions are nominal ± 0.004 inches.
5. Cermetek recommends that 0.040 inch diameter plated through holes are used with 0.060 inch
diameter pads.
6. Pin spacings are nominal ± 0.010 inches.
7. Pin placement to outside case edge is nominal ± 0.100 inches.
Figure 7. HS Modem Family Physical Dimensions.
Cermetek reserves the right to make changes in specifications at any time and without notice. The information furnished by
Cermetek in this publication is believed to be accurate and reliable. However, Cermetek assumes no responsibility for its use, or for
any infringements of patents or other rights of third parties resulting from its use. No license is granted under any patents or patent
rights of Cermetek.
Cermetek provides the user with a FCC/DOT Approved or Approvable device. However, Cermetek does not have influence over
nor knowledge of the specific user application environment. Therefore, for FCC Approved or Approvable devices, the user assumes
all risk for maintaining compliance to registration.
Printed in U.S.A
406 TASMAN DRIVE | SUNNYVALE CA 94089 | LOCAL: 408-752-5000 | TOLL FREE: 1-800-882-6271 | FAX: 408-752-5004
CERMETEK WEB SITE: http://www.cermetek.com | EMAIL: sales@cermetek.com
iModem Network WEB SITE: http://www.imodem.net/ or https://sunnyvale.imodem.net/
2004 Cermetek Microelectronics, Inc.
Page 19
Document No. 607-0003 Revision K6 (08/04)