XECOM XE2814 Datasheet

V.34 Modem for Data & Fax

XE2814

08-27-96

Description

Xecom's XE2814 combines high-speed V.34 data and Group III send/receive fax in a compact component.

The XE2814 is not just a modem chip but a complete modem including the telephone interface. It includes user transferable FCC Part 68 registration and can connect directly to the telephone line through an RJ11 jack. The modem connects to the host through a TTL level serial interface.

Xecom designed the XE2814 specifically for commercial and industrial systems with a need for high-speed communications and minimal space.

XE2814

PIN CONFIGURATION

Features

• Small Size; 2.75 " x 1.38" x 0.42"

• Modem control with "AT" commands

• Class 1 and Class 2 fax commands

• Data transfer up to 28,800 bps

• Send and receive fax to 14,400 bps

• MNP and V.42 Error Control

• MNP5 Data Compression to 57,600 bps

• MNP10 Error Control for Cellular links.

• V.42bis Data Compression to 115,200 bps

• Low power, single +5V supply Operating Power 900 mW (Typ.) Sleep mode: 50 mW (Typ.)

• NVRAM for modem configuration storage

xecom

1 40 2 39 3 38 4 37 5 36 6 35 7 34 8 33

9 32 10 31 11 30 12 29 13 28 14 27 15 16

20 21

NC NC

RXD

NC NC NC NC NC

/DTR

/CTS

TXD

/RTS

/RI

TIP

RING

VCC /DSR /DCD NC RESET NC NC NC NC NC OH NC NC NC

AMP GND

Block Diagram

2/XECOM XE2814

A 2.74 2.760 69.60 70.10 B 1.370 1.390 34.80 35.31 C 0.420 0.430 10.67 10.92 D 1.190 1.210 30.23 30.73 E 1.890 1.910 48.01 48.51 F 0.125 0.200 3.18 5.08 G 0.080 0.100 2.03 2.54 H 0.415 0.435 10.54 11.05 J 0.090 0.110 2.29 2.79 K 0.020 0.025 0.51 0.64

Mechanical Specifications - XE2814

Pins = 0.025 inch square pin All pins tin-plated

INCHES METRIC(MM)

PIN MIN MAX MIN MAX

Power Management:

The XE2814 has an integrated power management capability. If no activity is detected on the RXD, DTR, or RI the modem will, within 5 seconds, automatically go into a smart sleep mode. In this mode power consumption is typically less than 50 milliwatts.

Symbol Parameter Model Typ Max Units Comments

Power Supply Characteristics(TA = 0 - 70°C, Vcc = 5v ±5%)

Vcc Supply Voltage Both 5.0 5.25 Volts Icc Vcc Supply Current XE2814 180 200 mA Active, On Line

XE2814 10 mA Sleep Mode

PIN NAME I/O DESCRIPTION

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 Low, TTL. The function of this pin is set

by the &D command. Normally the modem ignores DTR.

11 \CTS O Clear to Send, output, active Low, TTL/CMOS. This pin regulates the flow

of data from the DTE during hardware flow control.

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 Low, TTL. This signal regulates the flow of

data from the modem during hardware flow control.

16 \RI O Ring Indicator, output, active Low, TTL. When low indicates the modem is

receiving a ring signal. 19 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 (0 volts) 22 AMP O Audio output function is determined by L & M commands and the value in

30 OH O DAA hookswitch relay is closed in the "off-hook" position connecting the

DAA to the telephone line. 36 RESET I Hardware reset pin, active High, TTL. Use of an external reset is not

recommended. Any signal applied to Pin 36 must remain high for a

minimum of 100 milliseconds. 38 \DCD O Data Carrier Detect, output, active Low, TTL/CMOS. Function is set by the

&C command and the value in register S21.

39 \DSR O Data Set Ready, output, active Low, TTL/CMOS. Function is set by the &S

command and the value in register S21.

40 Vcc — +5 Volts

XE2814 XECOM\3

Pin Descriptions

4/XECOM XE2814

Modem Applications Schematic

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

pin s of the RJ11 jack.

Recommended Parts

Reference Designation Recommended Part Number

L1, L2, L3 TDK CB30-1812

C1, C2, C3 Sprague 30GAT47, 470 pfd, 3000 Volts

J1, J2 Stewart SS6446NF

K1 Theta J LCA110

AT Commands

The XE2814 uses "AT" commands for control and configuration . Fax is supported by extensions to the AT commands.

Modes of Operation

The XE2814 has three operational modes; Command, Fax and Data.

Data Mode: The modem enters data mode

after it establishes a connection and issues a "CONNECT" result code. In Data Mode the modem modulates all signals on Transmit Data and sends them to the remote modem. The modem demodulates all signals from the remote modem and places them onto Received Data for the host equipment. When the modem exits data mode, it issues a "NO CARRIER" result code.

Command Mode: The XE2814 enters

command mode on application of power, reset, loss of the connection, or receipt of the escape code. In command mode the modem accepts commands from the host on Transmit Data. More than one command may be placed on each command line. Appropriate result codes are returned on Received Data.

Fax Mode: The modem enters Class 1 fax

mode on receipt of AT+FCLASS=1; AT+FCLASS=2 initiates Fax Class 2. Fax commands and responses are issued at 19,200 bits per second; the character format is 8 bits no parity. Fax commands are valid only in fax mode. The A/, ATO, AT&T and escape commands are not valid in fax mode.

XE2814 XECOM\5

Commands

AT command lines must follow a strict format. 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 for the A/ command, begins with the AT prefix. The "A" and "T" may be either both caps or both lower case but cannot be of different cases. The prefix identifies the speed and parity of the commands sent by the host. The modem determines speed by measuring the width of the incoming bits and parity by comparing the parity bits of the "A" and the "T." The XE2814 returns result codes at the speed and parity of the host.

Command Line - Multiple commands may be placed in a command line. Commands are executed in the sequence they appear. Spaces, inserted to improve legibility, 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 - The command buffer can hold only 40 characters, including the AT prefix. If the command buffer overflows, the modem issues an "ERROR" result code and commands are not executed.

A - Answer Command Bn - Select Communications Standard

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

D - Dial Command -

L = Re-dial last number P = Pulse dial T = Tone dial

S=n = Dial stored number

W = Wait for dial tone , = Pause for the duration ofr 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 opens* n=1 The switch hook relay closes

In - Modem Identification Ln - Speaker Volume -

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

6/XECOM XE2814

Command Line Editing - The backspace can be used to edit the command line. Hitting the backspace key, or Control and H simultaneously on some systems, erases the previous character in the command line. All of the characters can be erased except for the "A" and "T." 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.

Ommitted Parameters - Most commands include a parameter which determines the command function. When this parameter is omitted from the command string, it is assumed to be a 0.

Escape Characters - A three character escape sequence maybe entered while in data mode to switch the modem into command mode while remaining on line. The escape character, set by Register S2, must be entered 3 times in succession 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 precede and follow each result code.

AT Command List

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