Datasheet XE1276A Datasheet (XECOM)

xecom

XE1276A

2/97

Compact 1200 bps Modem

Description

The XE1276A is the successor to the XE1276.
Several improvements have been incorporated in
the XE1276A. Power consumption has been
reduced, an automatic Sleep mode has been
added and the XE1276A includes non-volatile
memory for storage of the "AT" Commands used
for modem control and configuration.

The XE1276A provides a replacement for the
CH1776. Most OEM's currently using the CH1776
can use the XE1276A without altering their existing
hardware or software. The XE2476 provides a
2400 bps upgrade in the same package design.

The XE1276A includes user transferable FCC Part
68 registration. This permits use of the XE1276A
without additional FCC Part 68 testing.

Block Diagram

Features

• Modem Protocols Supported:
V.22, V.21, Bell 212A and 103

• Pin compatible with the XE1276, XE2476 and
CH1776

• Command set: "AT" command set for modem
control and configuration.

• Modem Configuration stored in NVRAM

• Small Size: 2.00 inches long, 1.125 inches wide,

0.44 inches high.

• Single +5V supply

• Low power CMOS:
Operating: 200 mW (Typical)
Sleep: 50 mW (maximum)

PIN CONFIGURATION

TST

N/C
N/C

/DCD

/DTR

D/V

OHO

RXD

TXD

N/C

SPK

VO

VI

1 18
2 17
3 16
4
5
6

XE1276A

7

(Top View)

8
9
10
11
12
13

15

14

RI
GND
VCC

RING
TIP

XE1276A Mechanical Specifications

INCHES METRIC(MM)

PIN MIN MAX MIN MAX

A 1.990 2.010 50.55 51.05
B 1.115 1.135 28.32 28.83

C 0.420 0.430 10.67 10.92
D 0.100 0.120 2.54 3.05
E 0.890 0.910 22.61 23.11
F 0.090 0.110 2.29 2.79
G 0.090 0.110 2.29 2.79
H 0.190 0.210 4.83 5.33

I 0.020 0.025 0.51 0.64

J 0.125 0.200 3.18 5.08

Pins = 0.025 square pin
recommended hole size 0.056"

ABSOLUTE MAXIMUM 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.

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 50 mA On-Line All outputs

Disconnected

Icc Vcc Supply Current 7 10 mA Sleep Mode

Sleep Mode: The XE1276A 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 less than 50 milliwatts.

XECOM (2) XE1276A

Pin Descriptions

PIN NAME DESCRIPTION

1 TST This output is for Xecom test purposes only;
2 N/C No Connection
3 N/C No Connection
4 \DCD DCD, Data Carrier Detect, is an active low output from the modem. DCD goes low to

indicate receipt of a valid carrier signal.

5 \DTR DTR, Data Terminal Ready, is an active low input to the modem. DTR must be present for

the XE1276A to remain on line. If DTR goes high while the modem is on line, the modem
disconnects immediately. The XE1276A will not automatically answer an icoming call if DTR
is not active.

6 D/V The D/V, Data/Voice, output can be used to drive a relay to connect an auxiliary telephone

handset. D/V is high when the modem is off-hook And low when the modem is on-hook.

7 OH OH, Off-Hook, is an active high output which indicates that the XE1276A is connected to the

telephone line.

8 RXD RXD, Received Data, provides the serial data output path from the modem. A logic "high"

represents a "mark" and a logic "low" represents a "space".

9 TXD TXD, Transmit Data, provides the serial data input path from the host. A logic "high"

represents a "mark" and a low represents a"space", TTL.
10 N/C No Connection
11 SPK SPK, Speaker, provides the Audio output to the modem speaker. Speaker operation is

determined by the ATL and ATMM commands . This output can drive a 300 ohm load.
12 VO The Modem Line Interface permits placement of non-modem signals on the telephone line

through the modem's telephone interface. VO must be tied to VI for normal modem operation

and open to place non-modem signals on the line through VI.
13 VI VI, Voice Interface, provides a path for non-modem signals to be placed on the telephone line

through the modem's telephone interface. VI must be tied to VO for modem operation.
14 TIP Tip connection to the phone line(RJ11 pin3) from the internal DAA.
15 RING Ring connection to the phone line(RJ11 pin4) from the internal DAA.
16 Vcc +5 Volt power for the modem.
17 GND Ground reference for the modem.
18 RI RI, Ring Indicator, provides an active high output whenever a ring signal appears on the

telephone line.

XECOM (3) XE1276A

AT Commands

The XE1276A uses "AT" commands for modem config­uration. This section describes the command format
and lists the commands, registers and result codes.

Modes of Operation

The "AT" commands have two operational modes;
Command Mode and Data Mode.

Data Mode: The XE1276A enters data mode upon
connecting with a remote modem and issues an
appropriate "CONNECT" result code. In Data Mode the
modem sends all data presented on Transmit Data
(TXD) to the remote modem and places demodulated
data from the remote modem onto Received Data
(RXD). When the modem exits data mode, it issues the
"NO CARRIER" result code.

Command Mode: The XE1276A enters command
mode on power-up, reset, a lost connection, or receipt
of the escape code. In command mode the modem
accepts commands from the host on transmit data.
Appropriate result codes are returned on received data.

Command Line Format

Command lines issued to the modem follow a strict
format. Each command begins with the prefix AT. The
command line is stored in the command buffer and
executed upon receipt of a carriage return. Until
executed, the command line can be edited with the
backspace key.

Command Prefix - Commands, except A/, begin with
the AT prefix. The "A" and "T" may be both upper case
or both lower case but cannot be of different cases. The
prefix identifies the speed and parity of the commands
sent by the host. Speed is determined by measuring the
width of the incoming bits. Parity is determined by
comparing the parity bits of the "A" and "T."

Command Line - Commands may be strung together
in a single command line of up to 40 characters.
Commands are executed in the sequence they appear.
A carriage return terminates the command line and
causes the commands to be executed. Register S3
allows the user to select a character other than a
carriage return to terminate the command line.

Command Buffer - The command buffer stores up to
40 characters, including the AT prefix, from one
command line. Spaces may be inserted into the
command line without filling space in the command
buffer. If the command buffer overflows, the modem
issues an "ERROR" result code and commands are not
executed.

Command Line Editing - A backspace can be used to
edit a command line before execution. The backspace
key, (Control and H simultaneously on some systems),
erases the previous character in the command line.
Register S5 allows the user to select a character other
than a backspace as the command line editor.

Re-Execute Last Command - The A/ command
causes the modem to reexecute the last command line.
This command does not require the "AT" prefix.

Omitted Parameters - Most commands include a
parameter which determine the function setting. When
the command parameter is omitted from the command
string, it is assumed to be a 0.

Escape Characters - An escape sequence may be
entered while in data mode to switch the modem into
command mode while on line. The escape character,
set by Register S2, must be entered 3 times in
succession within a 1 second guard time to execute the
escape. The default escape sequence is "+++."

Result Codes - The modem issues a result code after
each action. Result codes may be provided as full
words, numeric codes or may be disabled all together.
Each result code ends with a carriage return when
numeric result codes are chosen. When full word result
codes are chosen, a Line feed and Carriage Return
preceed and follow each result code.

XECOM (4) XE1276A

XE1276A AT Command List

A - Answer Command -

Bn - Select Communications Standard

n=0 Selects CCITT standards
n=1 Selects Bell standards*

D - Dial Command -

P = Pulse dial
T = Tone dial
R = Connect as an answering modem
W = Wait for dial tone
, = Pause for the duration of S8
@ = Wait for silence
! = Switch hook flash
; = Return to the command state
Sn = Dial number stored in location n

En - Command Echo

n=0 Do not echo commands
n=1 Enable command echo*

Hn - Switch Hook Control -

n=0 Switch hook relay closes*
n=1 The switch hook relay opens

In - Modem Identification
Ln - Speaker Volume -

n=0 Low speaker volume
n=1 Low speaker volume
n=2 Moderate speaker volume*
n=3 High speaker volume

Mn - Speaker Activity -

n=0 Speaker off
n=1 Speaker on until carrier received*
n=2 Speaker remains on
n=3 Speaker on after dialing until carrier detected.

On - On Line

n=0 Return On Line with no retrain*
n=1 No response to remote test request.
n=2 Initiate Remote Digital Loopback

Xn - Result Code Set -

n=0 Responses 0-4*
n=1 Responses 0-5
n=2 Responses 0-6
n=3 Responses 0-5, & 7
n=4 Responses 0-8

Z - Reset -

&Cn - DCD Operation

n=0 DCD is forced active
n=1 DCD indicates a valid carrier signal*

&Dn - DTR

n=0 DTR is ignored by the modem
n=2 Modem disconnects if DTR revoked.*
n=3 The modem performs a soft reset when DTR

is revoked.

&F - Use XE2476 Defaults

&Tn - Test Modes

n=0 Exit test mode
n=1 Local analog loopback
n=3 Initiate local digital loopback
n=4 Respond to remote loop request*
n=5 Deny remote loop request
n=6 Initiate a Remote Digital loopback
n=7 Remote digital loopback w self-test
n=8 Local analog loopback w self-test

&V - View Active Profile ­&Wn - Store Profile -

n=0 Stores the current configuration in memory

location 0.

n=1 Stores the current configuration in memory

location 1.

&Yn - Recall Profile

n=0 Use memory location 0.
n=1 Use memory location 1.

Qn - Responses

n=0 Send responses *
n=1 No Responses

Sr? - Interrogate Register ­Sr=n - Set Register Value ­Vn - Result Codes -

n=0 Numeric Result Codes
n=1 English Word Result Codes*

&Zn=X- Store Number

* Indicates the default setting for the command as

shipped by Xecom.

XECOM (5) XE1276A

XE1276A S-Register Summary

REG. RANGE/UNITS DESCRIPTION DEFAULT

S0 0-255/rings Number of rings to answer on 001
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, &D, &C, Y 000
S22 Bit Mapped L, M, X, &T4, &T5, DTE speed and parity 118
S23 Bit Mapped &T4,&T5, DTE speed, parity 007
S27 Bit Mapped &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

XECOM (6) XE1276A

XE1276A Electrical Specifications

Parameter Min Typ Max Unit Comments

DTMF Level -2.2 0 dBm 3 second average
Modem Transmit Level -12 -10.5 -9.0 dBm 600 ohm line

Pulse Dialing Rate 10 pps
Pulse Dialing Make/Break 39/61 % USA
Billing Delay Interval 2.0 sec.

Phone Line Impedance Match 600 ohms
Ring Detect Sensitivity 38 150 VRMS Type B Ringer
Telephone Loop Current 20 100 milliamps Off-hook

Input High Voltage (TXD, DTR) 2.0 Volts

Input Low Voltage (TXD, DTR) 0.8 Volts
Output High Voltage 2.4 Volts RXD -100 microamps;

(DCD, RXD, RI, OH) DCD, RI, OH - 1.6 mamps
Output Low Voltage 0.4 Volts RXD - 1.6 milliamps;

(DCD, RXD, RI, OH) DCD, RI, OH - 6 milliamps

Output Drive Current (OH, D/V) 10 milliamps

FCC Part 68 Information

Registration Number - DWEUSA-21473-MD-E
Ringer Equivalence - 0.8B

XECOM (7) XE1276A

XE1276A Applications Schematic

Differences between the XE1276A and XE1276

In creating the XE1276A Xecom strived to make the new
product compatible with both the XE1276 and XE2476.
Unfortunately some features could not be supported in
the new product. We believe the improvements made
will benefit most XE1276 customers.

New Features: The XE1276A features reduced power
consumption and the addition of non-volatile memory for
modem configuration storage.

We reduced XE1276A power consumption in two ways.
First, we reduced operating power by 20% using new
low power components. Second, we added a sleep
mode. The XE1276A automatically enters sleep mode if
there is no activity for 5 seconds. In sleep mode power
consumption is reduced to less than 50 milliWatts.

XECOM (8) XE1276A

The addition of non-volatile memory permits the user to
configure the modem once and never configure it again.
It also permits storage of up to four telephone numbers
which can be recalled for dialing.

Unsupported XE1276 Features: The features lost in
the XE1276A redesign were the specialized interface
pins for Auto-answer, Command Mode, and Speed
Indication. The XE1276A does not support High-Speed
Indication on Pin 1, Command Mode Indication on Pin 2,
or Auto Answer Disabled on pin 3. Please contact
Xecom's Application Engineering Department to assist in
working around these lost features.

FCC Instructions

This product complies with part 68 of the FCC Rules and Regulations. 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 Connection 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 is useful to determine the quantity 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 you 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 [phone] 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) XE1276A

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.

X e com Incorporated
374 Turquoise Street, Milpitas, CA 95035

xecom

XECOM (10) XE1276A

Ph:408-945-6640 Fax:[phone]
http://www.xecom.com/xecom