XECOM XE2401L Datasheet

xecom

2400bps Serial Input Component Modem

XE2401L

02-13-96

Description

Xecom's XE2401L component modem is a complete 2400 bps data modem. Its compact size and TTL level, serial interface allows for quick integration into virtually any new or existing design. The XE2401L contains all of the circuitry required for complete modem operation, including a user transferable FCC Part 68 registration, allowing direct connection to the Telephone Network. The XE2401L was specifically designed to provide industrial systems manufacturers with a complete, highly integrated, compact solution for adding data communication to their products.

Block Diagram

Features

• Small Size 1.08” x 2.28” x 0.42”,

• FCC Part 68 Registered, user transferable

• Data Transfer at 2400, 1200 and 300 bps

• Supported Protocols:

- CCITT V.22bis, V.22, V.21

- Bell 212A, 103

• TTL serial interface interfaces with industry standard UART’s

• Single +5v supply

• Modem control with Industry standard “AT” command set

• Standard package allows easy upgrades to Fax (XE9624F) and 9600 bps (XE9601) operation

PIN CONFIGURATION

Reset

RXD

1 40 2 39 3 38

+5V \DSR \DCD

DTR\

AA\

CTS\

TXD

RTS\

HS\

RI\

TIP

RING

(Top View)

9 10 11 12 13 14 15 16

18 20 21

AMP GND

Mechanical Specifications - Package type 'C2'

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

Pins: 0.025" x 0.025" All pins tin-plated

Recommended hole size: 0.056"

WEIGHT

•

METRIC ENGLISH

31.75 grams 1.12 oz.

PIN 1 DOT

Pin Descriptions

PIN NAME I/O DESCRIPTION

1 RESET I 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 O 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 O Serial data output to the DTE (i.e. external UART). A logic "high"

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

9 \DTR I Data Terminal Ready, input, active LO, TTL. The function of this pin

is set by the &D command and the value in register S21.

2/XECOM XE2401L

PIN NAME I/O DESCRIPTION

10 \AA O Auto Answer enable indicator, output, active LO, TTL/CMOS. 11 \CTS O Clear to Send, output, active LO, TTL/CMOS. A low indicates the

modem is ready to accept data signals for transmission.

12 OH O 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 I 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 I Request to Send, input, active LO, TTL.

15 HS O High Speed indicator, output, active LO, TTL/CMOS. Low when

operating at 2400bps rate, high otherwise.

16 \RI O Ring Indicator, output, active LO, TTL. When low indicates the

modem is receiving a ring signal. 18 TIP --- Tip connection to the phone line (RJ11 pin3) from the internal DAA. 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 imput impdedence to the speaker

driver must be greater tha 300 ohms. 38 \DCD O Data Carrier Detect, output, active LO, TTL/CMOS. Function is set by

the &C command and the value in register S21.

39 \DSR O 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.

Note: No other pin positions are present, i.e. only 18 physical pins are on this device.

No pins are present at positions 4, 5, 6, 7, 8, 17, 19, 23 - 37

XE2401L XECOM\3

AT Commands

The XE2401L 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.

Modes of Operation

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

Data Mode: The XE2401L enters data mode after it connects with a remote modem and issues an appropriate "CONNECT" 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 XE2401L 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 editied with the backspace key.

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 can be used to edit 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 reexecute the last command line. This is the only command which does not require the "AT" prefix.

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.

Ommitted 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.

4/XECOM XE2401L

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