XE2486
xecom
8-97
Miniature 2400 bps Modem Module
Description
Features
Xecom's XE2486 is a miniature, low cost 2400 bit
per second modem.
It provides a complete
212A and 103
modem, including necessary memory and the
DAA in a package just 1.0 inch by 1.25 inches.
configuration.
User transferable FCC Part 68 registration is
included.
wide, 0.50 inches high.
The XE2486 was specifically designed to provide
OEM system designers with a quick, easy and
and custom modem configurations
low-cost way to integrate a 2400 bits per second
modem. Industry standard "AT" commands
provide modem control and configuration. The
Operating: 200 mW (Typ.)
XE2486 interfaces with the system host through a
Sleep mode: 50 mW (Typ. )
TTL level, serial interface.
Block Diagram
VCC
Serial I/O
TXD
RXD
\DTR
\DSR
\RI
\CTS
ROM
NVRAM
\DCD
Modem
Controller
Auxilliary I/O
TXA
Tip
RXA
Analog
\V-D
\HS
Front End
DAA
Ring
RST
\SLEEP
SPK
Gnd
XECOM
XE2486
XE2486 Mechanical Specifications
INCHES
METRIC(MM)
A
PIN MIN
MAX
MIN
MAX
A
1.240
1.260
31.50
32.00
B
0.990
1.010
25.15
25.65
C
0.490
0.510
12.45
12.95
D
0.120
0.140
3.05
3.56
E
0.090
0.110
2.29
2.79
F
0.060
0.080
1.52
2.03
B
G
0.090
0.110
2.29
2.79
H
0.790
0.810
20.07
20.57
Denotes Pin 1
Pins = 0.010 by 0.020 inches
C
D
G
G
F
E
F
H
Pin Configuration and Descriptions
PIN
NAME
DESCRIPTION
1
Ring
Ring provides half the two-wire con-
XE2486
nection to the telephone network,
RING
1
22
N/C
RJ-11 Pin 4. A 1500 volt barrier
TIP
2
21
RST
isolates Ring from all other circuits.
20
GND
This isolation must be preserved
RXA
3
19
VCC
TXA
4
18
/HS
throughout the system. The battery
SPK
5
17
/DCD
voltage on Ring may be positive or
N/C
6
16
/CTS
N/C
7
15
/RI
negative with respect to Tip.
/SLP
8
14
/DSR
N/C
9
13
/DTR
2
Tip
Tip provides half the two-wire con-
TXD
10
12
/V-D
nection to the telephone network,
RXD
11
RJ-11 Pin 3. A 1500 volt barrier
isolates Tip from all other circuits. This isolation must be preserved throughout
the system. The battery voltage on Tip may be positive or negative with respect
to Ring.
3,4
N/A
Not used; Do not connect any circuitry to these Pins.
XECOM
(2)
XE2486
Pin Descriptions continued
PIN
NAME
DESCRIPTION
5
SPK
SPK provides the audio output to a speaker. Speaker output is controlled by the
ATL and ATM commands. The input impedance to the speaker driver must be
greater than 300 ohms.
6, 7
N/C
No Connection
8
/SLP
This active low output indicates when the modem is in the sleep mode.
9
N/C
No Connection
10
TXD
TXD provides serial data input from the host. A logic high represents a "Mark"
and a low represents a "Space".
11
RXD
RXD provides serial data output to the host. A logic high represents a "Mark"
and a low represents a "Space".
12
/V-D
The Voice-Data ouptut can be used to drive an external relay for switching
between the modem and handset connected to the same telephone line.
13
/DTR
Data Terminal Ready is an active low input to the modem. The AT&D command
sets the function of DTR.
14
/DSR
Data Set Ready is an active low output from the modem. Its operation is
determined by the AT&S command.
15
/RI
Ring Indicator is an active low output which marks the presence of a ring on the
line.
16
/CTS
Clear to Send is not used on the XE2486; it will remain low at all times.
17
/DCD
Data Carrier Detect goes low to indicate receipt of a valid incoming carrier. The
AT&C1 command enables the carrier detect function.
18
/HS
This active low output indicates when the XE2486 has made a 2400 bps
connection.
19
VCC
VCC provides the +5 volt power required by the modem.
20
Gnd
Ground provides the common reference for the XE2486.
21
RST
This active high input cause a hardware reset in the XE2486. The reset pulse
must be held high for at least 10 milliseconds to correctly reset the modem.
22
N/C
No Connection
XECOM
(3)
XE2486
XE2486 Typical Connection Diagram
+5 Volts
RJ11
FB1
Tip
3
4
FB2
Ring
Reset
C1
C2
GND
XE2486
VCC
/HS
SPK
/DCD
/CTS
16C450
/RI
UART
/SLP
/DSR
/DTR
TXD
V/D
RXD
Note: RJ11 Pin assignments reference a 6-pin connector. Tip and Ring are the center pins of all RJ11
jacks.
Recommended Parts
Reference Designation
Description
Recommended Part Number
L1, L2
Ferrite Beads
TDK CB30-1812
C1, C2
Capacitors
Sprague 30GAT47, 470 pfd, 3000 Volts
J1
RJ11 Jack
Stewart SS6446NF
XECOM
(4)
XE2486
AT Commands
Modes of Operation
Command Buffer - The command buffer holds a
The XE2486"AT" commands provide two
maximum of 40 characters, including the AT
operational modes in the XE2486; Command
prefix. Space inserted into the command line do
Mode and Data Mode.
not fill space in the command buffer. Attempting to
load a longer command line causes the modem to
Data Mode: The XE2486 enters data mode after
issue an "ERROR" result code and the commands
it establishes a
modem link and issues a
are not executed.
"CONNECT" result code. In Data Mode the
modem transmits all signals on Transmit Data
Command Line Editing - A backspace can be
(TXD) to the remote modem and puts data from
used to edit the command line beforeexecution.
the remote modem onto Received Data (RXD).
The backspace erases the previous character in
When the modem exits data mode, it issues a "NO
the command line. Register S5 allows selection of
CARRIER" result code.
a character other than a backspace to edit the
command line.
Command Mode: The XE2486 enters command
mode on power-up, reset, a lost connection, or
Re-Execute Last Command - An "A/" causes the
escape code receipt.
In command mode the
modem to re-execute the last command line. This
modem accepts commands from the host on
command which does not require the "AT" prefix.
transmit data. The modem returns appropriate
responses on received data.
Om mitted Parameters - Most commands include a
parameter which determines how the functions will
Command Line Format
be set. When this parameter is omitted from the
Command lines issued to the modem follow a
command string, it is assumed to be a 0.
strict format. The ATprefix begins each command.
The command buffer stores the command line
Escape Characters - A 3-character escape
which is executed upon receipt of a carriage
sequence switches the modem from data to
return. Until executed, the command line can be
command mode while remaining on line. The
editied with a backspace.
escape character, Register S2, must be entered 3
times in succession within a 1 second guard time
Command Prefix - Each command begins with
to execute the escape. The default escape
the AT prefix. The "A" and "T" may be both upper
sequence is "+++."
case or both lower case but cannot be of different
cases. The prefix identifies the speed and parity of
Result Codes - The modem issues a result code
the host. The modem measures the width of
after each action. Result codes may be provided
incoming bits to determine speed and compares
as full words, numeric codes or may be disabled all
parity bits of the two characters to determine parity.
together. Each result code ends with a carriage
return when numeric result codes are chosen.
Command Line - A command line may include a
When full word result codes are chosen, a Line
series of commands. The modem executes such
Feed and Carriage Return preceed and follow
commands in the sequence they appear. A
each result code.
carriage return terminates the command line and
executes the commands. Register S3 allows
selection of another character to terminate the
command line.
XECOM
(5)
XE2486
AT Command List
An asterisk indicates the factory default
Xn - Result Code Set -
A - Answer Command -
n=0
Responses 0-4*
n=1 Responses 0-5 & 10
Bn - Select Communications Standard
n=2
Responses 0-6 & 10
n=0 Selects CCITT standards
n=3 Responses 0-5, 7 & 10
n=1 Selects Bell standards*
n=4
Responses 0-7 & 10
D - Dial Command -
Z - Reset -
P = Pulse dial
T = Tone dial
&Cn - DCD Operation
R =
Connect as an answering modem
n=0 DCD is forced active*
W = Wait for dial tone
n=1 DCD indicates a valid carrier signal
,
= Pause for the duration of S8
&Dn - DTR
@ =
Wait for silence
n=0
DTR is ignored by the modem*
!
= Switch hook flash
n=2 Modem disconnects if the host revokes
;
= Return to the command state
DTR.
En - Command Echo
n=3 The modem performs a soft reset when
n=0 Do not echo commands
DTR is revoked.
n=1 Enable command echo*
&F - Revert to Factory Defaults
Hn - Switch Hook Control -
&Ln - Line Type
n=0 Switch hook relay closes*
n=0 Modem operates on dial-up lines*
n=1 The switch hook relay opens
n=1 Modem operates on leased lines
In - Modem Identification
&Qn - Communications Format
Ln - Speaker Volume -
n=0 Sets the modem for normal, unbuffered
n=0
Low speaker volume
operation.
n=1
Low speaker volume
&Tn - Test Modes
n=2
Moderate speaker volume*
n=0 Exit test mode
n=3
High speaker volume
n=1 Local analog loopback
Mn - Speaker Activity -
n=3 Initiate local digital loopback
n=0 Speaker off
n=4 Respond to remote loop request*
n=1 Speaker on until carrier received*
n=5 Deny remote loop request
n=2 Speaker remains on
n=6 Intiate a Remote Digital loopback
n=3 Speaker on after dialing until carrier is
n=7 Remote digital loopback w self-test
detected.
n=8 Local analog loopback w self-test
On - On Line
&V - View Active Profile -
n=0 Return On Line with no retrain*
&Wn - Store Profile -
n=1 Initiate retrain while returning On line.
n=0 Stores the current configuration in
Qn - Responses
memory location 0.
n=0 Send responses *
n=1 Stores the current configuration in
n=1 No Responses
memory location 1.
Sr? - Interogate Register -
&Yn - Recall Profile
n=0 Use memory location 0.
Sr=n - Set Register Value -
n=1 Use memory location 1.
Vn - Result Codes -
&Zn=X- Store Number
n=0
Numeric Result Codes
n=1 English Word Result Codes*
XECOM
(6)
XE2486
S-Register Summary
REG.
RANGE/UNITS
DESCRIPTION
DEFAULT
S0
0-255/rings
Number of rings to answer on
000
S1
0-255/rings
Count number of incoming rings
000
S2
0-127/ASCII
Escape character
043
S3
0-127/ASCII
Carriage return character
013
S4
0-127/ASCII
Line feed character
010
S5
0-32,127/ASCII
Backspace character
008
S6
2-255/sec
Dial tone wait time
002
S7
1-60/sec
Wait time for remote carrier
030
S8
0-255/sec
Comma pause time
002
S9
1-255/0.1 sec
Carrier detect response time
006
S10
1-255/0.1 sec
Delay from loss of carrier to hang up
014
S14
Bit Mapped
E,Q,V,T,P,D,A,R accept/ignore
170
S16
Bit Mapped
Modem loopback tests
000
S18
0-255/sec
Modem test timer
000
S21
Bit Mapped
J, &R, &D, &C, &S, Y
000
S22
Bit Mapped
L, M, X, &P, &T4, &T5, DTE speed and parity
118
S23
Bit Mapped
&T4,&T5, DTE speed, parity
007
S27
Bit Mapped
&Q, &L, &X, B commands
064
Result Code Summary
DIGIT
CODE
WORD CODE MEANING
0
OK
Successfully executed command line
1
CONNECT
300 bps connection established
2
RING
Ring signal detected
3
NO CARRIER
Carrier not detected within Register S7 detect time
4
ErroR
Error found in command line; returns to command line
5
Connect 1200
1200 bps connection established
6
No dial tone
No dial tone detected within 5 Sec. after going off-hook
7
Busy
Busy signal detected after automatically dialing a call
8
No answer
Five seconds of silence was not detected when using the @ command in
the Dial command line
10
Connect 2400
Connection established at 2400 bps
XECOM
(7)
XE2486
Electrical Specifications
Absolute MAaximum Ratings*
SUPPLY VOLTAGE - Vcc
+6.5 Volts
DC INPUT VOLTAGE
-0.6 Volts to +6.5 Volts
STORAGE TEMPERATURE RANGE
-25° C TO +100° C
LEAD TEMPERATURE (Soldering, 2 sec per wave)
260° C
OPERATING TEMPERATURE RANGE
0 TO 70° C
*Exceeding these values may result in permanent damage to the device.
Telephone Interface Specifications
PARAMETER
MIN
TYP
MAX
UNIT
Telephone Line Impedance Match
600
ohms
Ring Detect Sensitivity (on hook, Type B ringer)
38
Vrms
Telephone Loop Current
20
100
mA
Power Supply Characteristics (TA = 0 - 70°C, Vcc = 5v ±5%)
Symbol Parameter
Min
Typ
Max
Units
Comments
Vcc
Supply Voltage
4.75
5.0
5.25
V
Icc
Vcc Supply Current
40
mA
All outputs Disconnected
Iccpd
Power Down Current
10
mA
Power Management: The XE2486 has an integrated, advanced power management capability. If no activity is
detected on the RXD, DTR, or RI lines the modem will automatically go into a smart power down mode. In this mode
power consumption is typically less than 50 milliwatts.
XECOM
(8)
XE2486
FCC Instructions
This product complies with Part 68 of the FCC Rules. With each device shipped, there is a label which
contains, among other information, the FCC Registration Number and Ringer Equivalence Number
(REN) for this product. You must, upon request, provide this information to your telephone company.
The mounting of this device in the final assembly must be made in such a manner as to preserve the high
voltage protection between the TIP/RING and the rest of the system. Typically, this may be accomplished
by maintaining a minimum spacing .100 mils between the TIP/RING Traces to the RJ-11C Jack and low
voltage portion of the system. No additional circuitry may be attached between TIP/RING and the
telephone line connection, unless specifically allowed in the rules.
The REN helps determine the number of devices you may connect to a telephone line and still have all of
these devices ring when the number is called. In most, but not all areas, the sum of the RENs of all
devices connected to one line should not exceed five (5.0). To be certain of the number of devices you
may connect to the line, as determined by the REN, you should contact the local telephone company to
determine the maximum REN for your calling area.
If your system causes harm to the telephone network, the telephone company may discontinue service
temporarily. If possible, they will notify you in advance. If advance notification is not practical, you will be
notified as soon as possible.
Your telephone company may make changes in its facilities, equipment, operations or procedures that
could affect proper functioning of your equipment. If they do, you will be notified in advance to give you
an opportunity to maintain uninterrupted telephone service.
If you experience trouble with this device, please contact XECOM at (408) 945-6640 for information on
obtaining service or repairs. The telephone company may ask you to disconnect this device from the
network until the problem has been corrected or until you are sure that the device is not malfunctioning.
The device may not be used on coin service lines provided by the telephone company (this does not
apply to private coin telephone applications which use standard telephone lines). Connection to party
lines is subject to state tariffs.
XECOM
(9)
XE2486
Terms of Sale
Devices sold by XECOM are covered by the warranty provisions appearing in its Terms of Sale only. XECOM
makes no warranty, express, statutory, implied, or by description regarding the information set forth herein, or
regarding the freedom of the described devices from patent infringement. XECOM makes no warranty of
merchantability or fitness for any purposes. XECOM reserves the right to discontinue production and change
specifications and prices at any time and without notice. This product is intended for use in normal commercial
applications. Applications requiring extended temperature range, unusual environmental requirements, or high
reliability applications, such as military, medical life-support or life-sustaining equipment, are specifically not
recommended without additional processing and authorization by XECOM for such application.
Xecom assumes no responsibility for the use of any circuitry other than circuitry embodied in a Xecom product. No
other circuits, patents, or licenses are implied.
Life Support Policy
Xecom's products are not authorized for use as Critical Components in Life Support Devices or Systems.
Life Support Devices or Systems are devices or systems which, (a) are intended for surgical implant into the body,
or (b) support or sustain life, and whose failure to perform, when properly used in accordance with instructions
provided in the labeling, can be reasonably expected to result in significant injury to the user.
A Critical Component is any component of a life support device or system whose failure to perform can be
reasonably expected to cause failure of the life support device or system, or to affect its safety or effectiveness.
Copyright, Xecom © 1997
While Xecom, Inc. has made every effort to ensure that the information presented here is accurate, Xecom will not be liable for any damages arising
from errors or omission of fact. Xecom reserves the right to modify specifications and/or prices without notice. Product mentioned herein are used for
identification purposes only and may be trademarks and/or registered trademarks of their respective companies.
Xecom Incorporated
374 Turquoise Street, Milpitas, CA 95035
xecom
Ph:408-945-6640 Fax:408-942-1346 E-Mail: Info@Cermetek.com
XECOM
XE2486