Datasheet XE2400 Datasheet (XECOM)

XECOM (1) XE2400

Low-Cost, Embeddable, Serial 2400bps Modem

XE2400

2/986

Description

Xecom's XE2400 provides the lowest cost
alternative for embedding a complete modem.
Its compact size, TTL level, serial interface and
low cost allows for quick integration into virtually
any new or existing equipment.

The XE2400 contains all of the circuitry required
for complete modem operation, including the
DAA. The XE2400 provides user transferable
FCC Part 68 registration, allowing direct
connection to the Telephone Network without
additional FCC testing.

Xecom designed the XE2400 specifically to
provide systems manufacturers with a quick, cost­effective way to integrate data communications
into their products. The low -speed data transfer
the XE2400 provides is ideal for applications with
small amounts of data to transfer in each session.
The combination of a complete, modular modem,
user transferable FCC Registration, the easily
integrated serial interface, and low cost makes
the XE2400 ideal for all applications which rely on
low speed communications

1 40
239
338

9
10
11
12
13
14
15
16

18

22

20 21

Reset

AR

RXD

DTR\

AA\

CTS\

OH

TXD

RTS\

HS\

RI\

TIP

RING

+5V
\DSR
\DCD

AMP
GND

PIN CONFIGURATION

Features

• Small Size 1.08” x 2.28” x 0.42”,

•

User Transferable FCC Part 68 Registration

• Data Transfer at 2400, 1200 and 300 bps

• Low Power operation:
On Line: 40 milliamps at 5 Volts
Sleep: <10 milliamps at 5 Volts

• TTL level serial interface

• Modem control with Industry standard “AT”
command set

• Pin compatible with a family of fax and higher
speed modems for an easy upgrade path

(Top View)

XECOM (2) XE2400

XE2400 Mechanical Specifications

INCHES METRIC(MM)

PIN MIN MAX MIN MAX

A 2.270 2.290 57.66 58.17
B 1.070 1.090 27.18 27.69
C 0.420 0.430 10.67 10.92
D 0.890 0.910 22.61 23.11
E 1.890 1.910 48.01 48.51
F 0.125 0.200 03.18 05.08
G 0.080 0.100 02.03 02.54
H 0.180 0.200 04.57 05.08
J 0.090 0.110 02.29 02.79
K 0.020 0.025 00.51 00.64

A

B

Pin 1 Identifier

C

E

D

J

H

G

F

K

PIN NAME DESCRIPTION

1 RESET External reset pin active HI, TTL. An internal circuit resets the modem when power

is applied, no external reset is required. Any external reset applied to the modem
must be applied for a minimum of 100 milliseconds.

2 AR Auxiliary Data/Voice Relay output, active HI, TTL/CMOS. When high the external,

auxiliary telephone set relay is closed and the modem is in the voice mode.

3 RXD Serial data output to the DTE (i.e. external UART). A logic "high" represents a

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

4-8 No Pin

9 \DTR Data Terminal Ready, input, active LO, TTL. The function of this pin is set by the &D

command and the value in register S21.

10 \AA Auto Answer enable indicator, output, active LO, TTL/CMOS.

XE2400 Pin Descriptions

XECOM (3) XE2400

PIN NAME DESCRIPTION

XE2400 Pin Descriptions

11 \CTS Clear to Send, output, active LO, TTL/CMOS. A low indicates the modem is ready

to accept data signals for transmission.

12 OH Off-Hook, output, active HI, TTL/CMOS. A high indicates the modem's hookswitch

relay is closed connecting the modem to the telephone line.

13 TXD Serial data input from the DTE (i.e. external UART). A logic "high" represents a "mark" and a

low represents a"space", TTL.
14 \RTS Request to Send, input, active LO, TTL.
15 HS High Speed indicator, output, active LO, TTL/CMOS. Low when operating at 2400bps rate,

high otherwise.
16 \RI Ring Indicator, output, active LO, TTL. When low indicates the modem is receiving a ring

signal.
17 No Pin
18 TIP Tip connection to the phone line (RJ11 pin3) from the internal DAA.
19 No Pin
20 RING Ring connection to the phone line (RJ11 pin4) from the internal DAA.

Caution: Observe design rules for Tip & Ring trace layout.

21 GND Ground.
22 AMP Audio output to speaker. Function is determined by L & M commands and the value in register

S22. The input impedance to the speaker driver must be greater than 300 ohms.

23-37 No Pin

38 \DCD Data Carrier Detect, output, active LO, TTL/CMOS. Function is set by the &C command and

the value in register S21.
39 \DSR Data Set Ready, output, active LO, TTL/CMOS. Function is set by the &S command and the

value in register S21.
40 Vcc +5 Volts.

XECOM (4) XE2400

XE2400 AT Commands

The XE2400 uses "AT" commands for configuration and
control. This section describes use of the AT command
format and lists the AT commands, Registers and Result
codes. XE2400 "AT" commands have two operational
modes; Command Mode and Data Mode.

Data Mode: The XE2400 enters data mode after it
connects with a remote modem and issues the
appropriate result code. In the Data Mode the modem
sends all data presented on Transmit Data (TXD) to the
remote modem and puts data from the remote modem
onto Received Data (RXD). When the modem exits
data mode, it issues a "NO CARRIER" result code.

Command Mode: The XE2400 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 - Each command, except the A/
command, begins with the AT prefix. The "A" and "T"
may be either both upper case or both lower case but
cannot be of different cases. The prefix identifies the
speed and parity of the commands sent to the modem
by the host. Speed is determined by measuring the
width of the incoming bits. Parity is determined by
comparing the parity bit of the "A" and the "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.
Spaces may be inserted into the command line but do
not fill space in the command buffer. 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 - No more than 40 characters,
including the AT prefix, may be loaded into the
command buffer. If the command buffer overflows, the
modem issues an "ERROR" result code and commands
are not executed.

Command Line Editing - The backspace edits a
command line before it is executed. 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 to edit the command line.

Re-Execute Last Command - The A/ command causes
the modem to re-execute the last command line. This is
the only command which does not require the "AT"
prefix.

Omitted Parameters - Most commands include a
parameter which determines how the functions will be
set. When the command parameter is omitted from the
command string, it is assumed to be a 0.

Escape Characters - A 3 character escape sequence
maybe 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 (5) XE2400

XE2400 AT Command List

An asterisk indicates the factory default
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

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 is

detected.

On - On Line

n=0 Return On Line with no retrain*
n=1 Initiate retrain while returning On line.

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*

Xn - Result Code Set -

n=0 Responses 0-4*
n=1 Responses 0-5 & 10
n=2 Responses 0-6 & 10
n=3 Responses 0-5, 7 & 10
n=4 Responses 0-7 & 10

Yn - Long Space Disconnect -

n=0 Disabled *
n=1 Enabled

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 the host revokes DTR.
n=3 The modem performs a soft reset when DTR

is revoked.

&F - Revert to Factory Defaults
&Gn - Guard Timer -

n=0 None *
n=1 550 Hz Guard Timer
n=2 1800 Hz Guard Timer

&Ln - Line Type

n=0 Modem operates on dial-up lines*
n=1 Modem operates on leased lines

&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 -

XECOM (6) XE2400

S0 0-255/rings Number of rings on which the modem will answer 000
S1 0-255/rings Count number of incoming rings (read only) 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

REG. RANGE/UNITS DESCRIPTION DEFAULT

XE2400 S-Registers

XE2400 Result Codes

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) XE2400

ABSOLUTE MAXIMUM RATINGS*

XE2400 Electrical Specifications

SUPPLY VOLTAGE - Vcc +6.5 Volts

DC INPUT VOLTAGE -0.6 Volts to +6.5 Volts

STORAGE TEMPERATURE RANGE -25° C TO +85° C

LEAD TEMPERATURE(Soldering, 2sec/wave) 260° C

OPERATING TEMPERATURE RANGE 0 TO 70° C

*Exceeding these values may result in permanent damage to the device.

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 Sleep Mode Current 8 mA

XE2400 Power Supply Characteristics

(TA = 0 - 70°C, Vcc = 5v ±5%)

The XE2400 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 60 milliwatts.

Telephone Line Impedance Match 600 ohms
Ring Detect Sensitivity (on hook, Type B ringer) 38 Vrms
Telephone Line Holding Current 20 100 mA

Telephone Line Interface Specifications

PARAMETER MIN TYP MAX UNIT

XECOM (8) XE2400

Tip
Ring

L1

L2

C1

C2

J1

VCC

Reset

TXD

RXD

+5 Volts

50K

.2 ufd

250 ufd

.05 ufd

10 ohms

8 ohm .5 W
Speaker

AMP

4 3

Line

GND

LM386

/RI

/RTS

/CTS

/DTR

/DSR

/DCD

OH

XE2400

16C450

UART

/DSR

/DCD

SIN

/DTR

/CTS

SOUT
/RTS

/RI

XE2400 Applications Schematic

Note: RJ11 Pin assignments reflect a 6-pin connector. Tip and Ring are always the center pins of the

RJ11 jack.

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 (9) XE2400

FCC Instructions

The XE2400 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 (10) XE2400

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.

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.

Terms of Sale

Life Support Policy

Copyright, Xecom © 1998
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
Ph:408-945-6640 Fax:[phone] E-Mail: [email protected]