Cermetek DataSheet for product CH1794, CH1799 and CH2056

HIGH SPEED Modem and FAX FAMILY

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

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.

Page 1

Document No. 607-0003 Revision K6 (08/04)

Cermetek Microelectronics, Inc.

HIGH SPEED Modem and FAX FAMILY

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

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.

Page 2

Document No. 607-0003 Revision K6 (08/04)

Cermetek Microelectronics, Inc.

HIGH SPEED Modem and FAX FAMILY

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.

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.

Page 3

Document No. 607-0003 Revision K6 (08/04)

Cermetek Microelectronics, Inc.

HIGH SPEED Modem and FAX FAMILY

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

Odd

Even

None

Odd

11*

Even

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

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,

 2004 Cermetek Microelectronics, Inc.

Page 4

Document No. 607-0003 Revision K6 (08/04)

Cermetek Microelectronics, Inc.

HIGH SPEED Modem and FAX FAMILY

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

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

EARTH GROUND

CTS

UART

TXD

DTR

Vcc

22K

LM393

RST

LM393

4.7K

EXTERNAL RESET

10K

4.7uF

+5V

.1uF

Isolated

10K

GND

Envelope

Ring Detect

Figure 4.

HS Modem Family Application Diagram.

 2004 Cermetek Microelectronics, Inc.

Page 5

Document No. 607-0003 Revision K6 (08/04)

Cermetek Microelectronics, Inc.

HIGH SPEED Modem and FAX FAMILY

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

will reconfigure to its default state with the line carrier

Result: <CR><LF>

modulation speed set to:

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.

Page 6

Document No. 607-0003 Revision K6 (08/04)

Cermetek Microelectronics, Inc.

HIGH SPEED Modem and FAX FAMILY

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

CH1786

HS Modem Family

18) unless the DTE is forced to a higher speed by

RING

selection of data compression.

In this case, the

TIP

maximum DTE to modem speed is 230.4kbps (result

RXA

code20).

TXA

Extensions to the basic result code set may be

SPK

specified by Register S95, which allows for the use of

result codes 40-64, 165-194.

IMPORTANT NOTE

SLEEP

OPEN*

Result codes 53-64 are supported by the CH1799

and CH2056.

Result codes 165-194 are only

TXD

supported by the CH2056. To obtain a detailed

RXD

status report for a given modem communication

configuration, use the AT\V1 command. Executing

V/D

OPEN*

this command at setup will cause the modem to

DTR

connect and return a message on line consisting of

DSR

<DTE speed> <modulation> <error protocol> <line

speed of connection>.

CTS (FX only)

CTS

DCD

LEASED LINE OPTION

NC*

The CH1799LL is a leased line version of the CH1799.

Whereas the CH1799 requires an active voltage

V CC

bearing or wet PSTN line for normal operations

GND

(typically, 48VDC on-hook line voltage), the CH1799LL

RST

is designed to operate over a non-voltage bearing or

dry line.

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

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.

HIGH SPEED Modem and FAX FAMILY

Table 3.

HS Modem Family Pin Descriptions.

NAME

I/O

FUNCTION

RING

I/O

TELCO/TELSET INPUT . Directly connects to the telephone line’s RING lead through a

user supplied RJ-11C jack.

TIP

I/O

TELCO/TELSET INPUT . Directly connects to the telephone line’s TIP lead through a user

supplied RJ-11C jack.

I/O

ANALOG VOICE INJECTED . Input (See Figure 5). 2.2V P-P max. Let float if not used.

No connection.

SPK

SPEAKER . Audio output for speaker. See speaker control diagram.

No connection.

TXD

TRANSMIT DATA .

Serial Transmit data input.

Marking, or a binary 1 condition, is

transmitted when a HIGH is asserted.

RXD

RECEIVE DATA . Serial Receive data output. Received marking or a binary 1 condition is

indicated by a HIGH.

No connection.

DTR

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.

DSR

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.

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.

CTS

CLEAR TO SEND . Active LOW. Indicates that the modem is ready to accept data from

the DTE.

DCD

DATA CARRIER DETECT . LOW indicates a data carrier from a remote modem has been

detected. This feature must be enabled using the &C1 command.

No connection.

VCC

POWER SUPPLY . 5 Volts ± 5%. Note: Noise should be less than 25mV peak-to-peak.

GRD

GROUND . Note: Noise should be less than 25mV peak-to-peak.

RST

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.

RTS

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.

HIGH SPEED Modem and FAX FAMILY

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

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

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

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.

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

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

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.

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

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

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.

HIGH SPEED Modem and FAX FAMILY

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

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.

HIGH SPEED Modem and FAX FAMILY

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.

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

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

Dials with touch-tone (T)

Detects busy signal (ATX4)

Short

Full word result codes – non-extended

X X

Pulse dial make/break ratio = 39/61-10pps

CONNECT

X X

Test timer set to 0 seconds, test modes disabled

RING

X X

Inactivity timer set to 0 minutes

CTS always active

NO CARRIER

X X

DSR is ignored

ERROR

X X

DCD is ignored

CONNECT 1200

X X

RTS to CTS delay - .01 seconds

NO DIAL TONE

X X

DTR always active – hang up after transition

BUSY

Long space disconnect disabled

NO ANSWER

X X

Speaker enabled but off when receiving carrier

CONNECT 0600

X X

Speaker volume set to low

CONNECT 2400

X X

Local modem will not grant RDL request from remote

CONNECT 4800

X X

modem

CONNECT 9600

X X

Guard tones disabled

CONNECT 7200

X X

Minimum DTR pulse width = .05 seconds

CONNECT 12000

X X

Ring count – 00

CONNECT 14400

X X

Escape code character = 43 (+)

CONNECT 19200

X X

 2004 Cermetek Microelectronics, Inc.

Page 11

Document No. 607-0003 Revision K6 (08/04)

Cermetek Microelectronics, Inc.

HIGH SPEED Modem and FAX FAMILY

Figure 5. Schematic Illustrating Implementation of Voice Injection Feature.

Table 5A. Summary

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

Terse

Verbose or Long

Terse

Verbose or Long

Short

CONNECT 38400

X X

+MRR: 28800

CONNECT 57600

X X

CARRIER 16800

CONNECT 115200

X X

CARRIER 21600

CONNECT 230400

X X

CARRIER 24000

CONNECT

X X

CARRIER 26400

75TX/1200RX

CARRIER 28800

CONNECT

X X

+DR: ALT

1200TX/75RX

+DR: V42B

DELAYED

+DR: None

BLACKLISTED

+ER: NONE

FAX

X X

+ER: LAPM

DATA

X X

+ER: ALT

CONNECT 33600

Table 5B. CH1799 Extended Result Codes.

CONNECT 31200

Result Code Form

n is ATXn

Command

IMPORTANT NOTE

Terse

Verbose or Long

This note applies to Tables 5A, 5B, and 5C. An

“X” in a column indicates that the message (either

Short

the long form if verbose, or the value only for short

+MRR: 300

form) will be generated when that particular value

+MRR: 1200/75

of “n” (shown at the top of the column) has been

+MRR: 75/1200

selected by the use of ATXn . A numeral indicates

+MRR: 1200

which less explicit message (verbose or short

+MRR: 2400

form) will be output for that X option.

+MRR: 4800

+MRR: 7200

Table 5C. CH2056 Extended Result Codes.

+MRR: 9600

Result Code Form

n is ATXn

+MRR: 12000

Command

+MRR: 14400

Terse

Verbose or Long

+MRR: 16800

+MRR: 19200

Short

+MRR: 21600

165

CONNECT 32000

X X X X X

+MRR: 24000

166

CONNECT 34000

X X X X X

+MRR: 26400

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.

HIGH SPEED Modem and FAX FAMILY

Table 5C. CH2056

Extended

Result

Codes

Table 6A. Summary of Basic AT Commands

(Continuation).

Result Code Form

n is ATXn

Command

Function

Command

H, H0

Initiate a hang-up sequence

Terse

Verbose or Long

If on-hook, go off-hook and enter

command mode

Short

Set low speaker volume

168

CONNECT 38000

Set low speaker volume

169

CONNECT 40000

Set medium speaker volume

170

CONNECT 42000

Set high speaker volume

171

CONNECT 44000

Speaker off

172

CONNECT 46000

Speaker on during hand shaking and

173

CONNECT 48000

speaker off while receiving carrier

174

CONNECT 50000

Speaker on during hand shaking and

175

CONNECT 52000

while receiving carrier

176

CONNECT 54000

Speaker

off

during

dialing

and

177

CONNECT 56000

receiving Carrier and speaker on

178

CONNECT 23040

during answering

180

CONNECT 28000

Go on-line

181

CONNECT 29333

Go on-line and initiate a retrain

182

CONNECT 30667

sequence

183

CONNECT 33333

Allow result codes to DTE

184

CONNECT 34667

Inhibit result codes to DTE

185

CONNECT 37333

Select S-Register as default

186

CONNECT 38667

Sn?

Return the value of S-Register n

187

CONNECT 41333

Sn=v

Set S-Register n to value (v)

188

CONNECT 42667

Report short form (terse) result codes

189

CONNECT 45333

Report long form (verbose) result

190

CONNECT 46667

codes

191

CONNECT 49333

Report DTE speed

192

CONNECT 50677

Report line speed, EC protocol and

193

CONNECT 53333

DTE speed

194

CONNECT 54377

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,

Re-execute command

enabled, and dial tone not detected),

Go off-hook and attempt to answer call

NO ANSWER and ERROR

Select CCITT connection at 300 or

Z0, Z1

Initiate modem soft reset.

Restore

1200bps

stored profile 0 or 1 after reset

Sect Bell connection at 300 or 1200bps

&C0, &C1

Force DCD active regardless of the

Dial modifier

carrier state or allow DCD to follow the

Pulse Dial

carrier state

Touch Tone Dial

&D0

Modem ignores DTR. (Default)

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

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

Enable command echo

&K5

Enable transparent XON/XOFF flow

Disable command echo

control

 2004 Cermetek Microelectronics, Inc.

Page 13

Document No. 607-0003 Revision K6 (08/04)

Cermetek Microelectronics, Inc.

HIGH SPEED Modem and FAX FAMILY

Table 6B. Summary of Basic AT Commands.

Command

Function

Command

Function

&Q6

Select

asynchronous

operation

OPERTING MODE COMMANDS

normal mode

\N0

Select normal speed buffered mode

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

Reports product code

\Bn

Send break of n x 100 msec (n=0 to 9)

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.

HIGH SPEED Modem and FAX FAMILY

Table 7. S-Register Summary.

Firmware

Factory

Function

Range

Units

Saved

Defaults

Rings to Auto-Answer

0-255

rings

000

Ring Counter

0-255

rings

000

Escape Character

0-255

ASCII

043

Carriage Return Character

0-127

ASCII

013

Line Feed Character

0-127

ASCII

010

Backspace Character

0-255

ASCII

008

Wait Time before Dial Tone or Blind Dialing

2-255

002

Wait Time for Carrier, Silence or Dial Tone

1-255

050

Pause Time for Dial Delay Modifier

0-255

002

Carrier Detect Response Time

1-255

0.1s

006

S10

Carrier Loss Disconnect Delay

1-255

0.1s

014

S11

DTMF Tone Duration

095

S12

Escape Prompt Delay

0-255

0.02s

050

S13

Reserved

000

S14

General Bit Mapped Options Status

138 (8AH)

S15

Reserved

000

S16

Test Mode Bit Mapped Options Status (&T)

000

S17

POS Option

000

S19

Reserved

000

S20

Reserved

000

S21

V.24/General Bit Mapped Options Status

052 (34H)

020 (14H)

S22

Speaker/Results Bit Mapped Options Status

117 (75H)

S23

General Bit Mapped Options Status

000

S24

Sleep Inactivity Timer

0-255

000

S25

Delay to DTR off

0-255

s or 0.01s

005

S26

RTS-to-CTS Delay

0-255

0.01s

001

S27

General Bit Mapped Options Status

073 (49H)

S28

General Bit Mapped Options Status

000

S29

Flash Dial Modifier

0-255

0.01s

070

S30

Disconnect Inactivity Timer

0-255

10s

000

S31

General Bit Mapped Options Status

192 (C0H)

S36

LAPM Failure Control

007

S37

Line Connection Speed

000

S38

Delay Before Forced Hang-up

0-255

020

S39

Flow Control Bit Mapped Options Status

003

S40

General Bit Mapped Options Status

104 (68H)

S41

General Bit Mapped Options Status

195 (C3H)

S43-S45

Reserved

S46

Data Compression Control

138

S48

V.42 Negotiation Control

007

S82

LAPM Break Control

000

S86

Call Failure Indeification

0-26

021

S91

PSTN Transmit Attenuation Level

0-15

dBm

S92

FAX Transmit Attenuation Level

0-15

dBm

S95

Result Code Messages Control

000

S210

V.34 Symbol Rate

0-255

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.

HIGH SPEED Modem and FAX FAMILY

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.

HIGH SPEED Modem and FAX FAMILY

Table 8. HS Modem Electrical Specifications.

Symbol

Characteristic

Min.

Typ.

Max.

Units

V CC

Positive Supply Voltage

4.5

5.0

5.5

I CC Off Hook

Operating Current @

175

V CC = 5.5V when modem is Off Hook

I CC On Hook

Operating Current @

170

V CC = 5.5V when modem is Off Hook

V IH

High Level Input Voltage*

2.0

V IL

Low Level Input Voltage*

0.8

VT+

Positive Hysteresis Threshold for RESET Pin

2.5

VT-

Negative Hysteresis Threshold for RESET Pin

0.5

V OH

High Level Output (I OH = 0.5 mA)*

2.4

V OL

Low Level Output (I OL = 1.6 mA)*

0.6

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)

Capacitive Load (RST)

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

Ohm

Trans Hybrid Loss

600 Ohm, RXA, TXA

Ring Voltage Loop

110V

250V

V PP

On 48VDC line voltage for sustained

periods

Line Loop Cur