Xecom's XE2486 is a miniature, low cost 2400 bit
Supported Protocols: V.22bis, V.22, V.21, Bell
per second modem.
It provides a complete
212A and 103
modem, including necessary memory and the
"AT" commands for modem control and
DAA in a package just 1.0 inch by 1.25 inches.
User transferable FCC Part 68 registration is
Small Size: 1.25 inches long, 1.0 inches
wide, 0.50 inches high.
The XE2486 was specifically designed to provide
NVRAM stores commonly dialed numbers
OEM system designers with a quick, easy and
and custom modem configurations
low-cost way to integrate a 2400 bits per second
Single +5V supply
modem. Industry standard "AT" commands
Low power CMOS:
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.
XE2486 Mechanical Specifications
Denotes Pin 1
Pins = 0.010 by 0.020 inches
Pin Configuration and Descriptions
Ring provides half the two-wire con-
nection to the telephone network,
RJ-11 Pin 4. A 1500 volt barrier
isolates Ring from all other circuits.
This isolation must be preserved
throughout the system. The battery
voltage on Ring may be positive or
negative with respect to Tip.
Tip provides half the two-wire con-
nection to the telephone network,
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
Not used; Do not connect any circuitry to these Pins.
Pin Descriptions continued
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.
This active low output indicates when the modem is in the sleep mode.
TXD provides serial data input from the host. A logic high represents a "Mark"
and a low represents a "Space".
RXD provides serial data output to the host. A logic high represents a "Mark"
and a low represents a "Space".
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.
Data Terminal Ready is an active low input to the modem. The AT&D command
sets the function of DTR.
Data Set Ready is an active low output from the modem. Its operation is
determined by the AT&S command.
Ring Indicator is an active low output which marks the presence of a ring on the
Clear to Send is not used on the XE2486; it will remain low at all times.
Data Carrier Detect goes low to indicate receipt of a valid incoming carrier. The
AT&C1 command enables the carrier detect function.
This active low output indicates when the XE2486 has made a 2400 bps
VCC provides the +5 volt power required by the modem.
Ground provides the common reference for the XE2486.
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.
XE2486 Typical Connection Diagram
Note: RJ11 Pin assignments reference a 6-pin connector. Tip and Ring are the center pins of all RJ11
Recommended Part Number
Sprague 30GAT47, 470 pfd, 3000 Volts
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 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
AT Command List
An asterisk indicates the factory default
Xn - Result Code Set -
A - Answer Command -
n=1 Responses 0-5 & 10
Bn - Select Communications Standard
Responses 0-6 & 10
n=0 Selects CCITT standards
n=3 Responses 0-5, 7 & 10
n=1 Selects Bell standards*
Responses 0-7 & 10
D - Dial Command -
Z - Reset -
P = Pulse dial
T = Tone dial
&Cn - DCD Operation
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
DTR is ignored by the modem*
= Switch hook flash
n=2 Modem disconnects if the host revokes
= Return to the command state
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
Low speaker volume
Low speaker volume
&Tn - Test Modes
Moderate speaker volume*
n=0 Exit test mode
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
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
Numeric Result Codes
n=1 English Word Result Codes*
Number of rings to answer on
Count number of incoming rings
Carriage return character
Line feed character
Dial tone wait time
Wait time for remote carrier
Comma pause time
Carrier detect response time
Delay from loss of carrier to hang up
Modem loopback tests
Modem test timer
J, &R, &D, &C, &S, Y
L, M, X, &P, &T4, &T5, DTE speed and parity
&T4,&T5, DTE speed, parity
&Q, &L, &X, B commands
Result Code Summary
WORD CODE MEANING
Successfully executed command line
300 bps connection established
Ring signal detected
Carrier not detected within Register S7 detect time
Error found in command line; returns to command line
1200 bps connection established
No dial tone
No dial tone detected within 5 Sec. after going off-hook
Busy signal detected after automatically dialing a call
Five seconds of silence was not detected when using the @ command in
the Dial command line
Connection established at 2400 bps
Absolute MAaximum Ratings*
SUPPLY VOLTAGE - Vcc
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)
OPERATING TEMPERATURE RANGE
0 TO 70° C
*Exceeding these values may result in permanent damage to the device.
Telephone Interface Specifications
Telephone Line Impedance Match
Ring Detect Sensitivity (on hook, Type B ringer)
Telephone Loop Current
Power Supply Characteristics (TA = 0 - 70°C, Vcc = 5v ±5%)
Vcc Supply Current
All outputs Disconnected
Power Down Current
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.
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.
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.
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