XECOM XE2814 Datasheet

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xecom

08-27-96

 

XE2814

 

 

V.34 Modem for Data & Fax

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.

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

XE2814

PIN CONFIGURATION

Block Diagram

NC

1

40

VCC

NC

2

39

/DSR

RXD

3

38

/DCD

NC

4

37

NC

NC

5

36

RESET

NC

6

35

NC

NC

7

34

NC

NC

8

33

NC

/DTR

9

32

NC

NC

10

31

NC

/CTS

11

30

OH

NC

12

29

NC

TXD

13

28

NC

/RTS

14

27

NC

NC

15

 

 

/RI

16

 

 

TIP

18

22

AMP

 

 

RING

20

21

GND

 

 

 

 

Power Management:

Mechanical Specifications - XE2814

 

 

INCHES

METRIC(MM) Pins = 0.025 inch square pin

 

 

 

 

 

 

 

All pins tin-plated

 

PIN

MIN

MAX

MIN

MAX

 

 

 

 

 

A

2.74

2.760

69.60

70.10

 

 

 

B

1.370

1.390

 

 

 

 

 

C

0.420

0.430

 

 

 

 

 

D

1.190

1.210

 

 

 

 

 

E

1.890

1.910

 

 

 

 

 

F

0.125

0.200

 

 

 

 

 

G

0.080

0.100

 

 

 

 

 

H

0.415

0.435

 

 

 

 

J0.090 0.110

K0.020 0.025

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

 

Symbol

Parameter

 

 

Model

 

 

 

 

 

 

 

Typ

 

 

 

 

 

Max

 

 

 

Units

 

 

 

 

 

 

 

 

Comments

 

 

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

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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.

2/XECOM

XE2814

Pin Descriptions

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

 

 

 

register S22. This output can drive a 50Kohm load.

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

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

 

 

4/XECOM

XE2814

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.

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.

XE2814

XECOM\5

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

A - Answer Command -

 

En - Command Echo

Bn - Select Communications Standard

 

n=0

Do not echo commands

 

n=1

Enable command echo*

n=0

Selects CCITT standards

 

 

 

 

n=1

Selects Bell standards*

 

Hn - Switch Hook Control -

D - Dial Command -

 

n=0 Switch hook relay opens*

 

n=1 The switch hook relay closes

L

=

Re-dial last number

 

 

 

 

P

=

Pulse dial

 

In - Modem Identification

T

=

Tone dial

 

Ln - Speaker Volume -

S=n =

Dial stored number

 

 

n=0

Lowest speaker volume

W

=

Wait for dial tone

 

 

n=1

Low speaker volume

,

=

Pause for the duration ofr S8

 

 

n=2

Moderate speaker volume*

@ = Wait for silence

 

 

n=3

High speaker volume

! = Switch hook flash

 

 

 

 

;

=

Return to the command state

 

 

 

 

 

 

 

 

 

6/XECOM

XE2814

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