Westermo TD-22 User Manual

PTT Modem

INSTALLATION MANUAL

6177-2203

www.westermo.se

TD-22 AC

TD-22 DC

©

Westermo Teleindustri AB • 1998 • REV A

Galvanic

Isolation

Transient

ProtectionCEApproved

36177-2203

TABLE OF CONTENTS

INTRODUCTION

................................................................................................................................................ 4

SAFETY

................................................................................................................................................................................... 4

SPECIFICATIONS

.................................................................................................................................................. 5

INSTALLATION

....................................................................................................................................................... 5

RS-232 CONNECTIONS

........................................................................................................................... 6

LINE CONNECTIONS

.................................................................................................................................. 6

TYPICAL TD-22 LINE CONNECTIONS

.......................................................................... 7

DIP SWITCH SETUP

............................................................................................................................ 8–10

LED STATUS INDICATORS

............................................................................................................ 11

DTE COMMAND LINES

........................................................................................................................ 12

AT COMMAND SET

....................................................................................................................... 13–32

RESULT CODES

.................................................................................................................................................. 33

S-REGISTERS

................................................................................................................................................. 34–42

BLOCK DIAGRAM

.......................................................................................................................................... 42

APPLICATION EXAMPLES

.................................................................................................... 43–46

GLOSSARY

...................................................................................................................................................... 47–50

4 6177-2203

Introduction

The Westermo TD-22 is an industrialised dial and leased line modem. This modem has been
developed to be used in industrial applications and has some features you would not expect to find on
a normal modem.

Terminal data rates of up to 19.2 kbit/sec can be handled using data compression and error
correction. Direct mode connections with the maximum line modulation speed of 2,400 bit/sec can
be made.

Lease line 2 and 4 wire connections can be made as well as multidrop half duplex V.23 connections.
The modem can also be used on ordinary twisted pair cables to provide long distance asynchronous
communications.

A watchdog facility continually monitors the power supply and internal hardware as well as the
operational software. In the event of a problem the modem automatically resets. This feature has
been included to make the unit more suitable for use in unmanned locations.

The TD-22 is available in two standard versions for power supply by 230VAC or 12-36VDC. Special
115VAC and 36-55VDC models are also available on request.

Westermo have implemented commands often left out of standard modems like &D to allow
hardware controlled dial out on receipt of a hardware signal and &A to prevent aborts on connection
when extra characters are received.

The TD-22 can handle 11 data bits and has a special 2 stop bit mode to allow the unit to be used in
applications many modems can’t handle.

The TD-22 has been designed with the engineer in mind, hence the extensive information on the
command set, S registers, DIP switched and error codes. We have endeavoured to include all
necessary information however if you need more please do not hesitate to call us.

Safety

This equipment should only be installed by professional service personnel. If the unit is intended for
permanent connection to mains supply, there should be a readily accessible
disconnect device (circuit breaker) incorporated into the fixed wiring.

All ports on this equipment are designed for connection to TNV circuits.
The mains connection is classified as excessive voltage
Description of the above classifications are given in EN60950:1992.

56177-2203

Specifications

Installation

The modem should be
connected in the following
way:

Power connection is made
through screw-block at bottom
right corner.
For 115VAC or 230VAC it is
a 3-pole connector, and for 12­36 or 36-55V DC a 2-pole
connector
Computers or other equipment
are connected through an
RS-232 connection .
This connection can be made
either to the 25-pole D-sub or
the 9-pole screw connector.
Do not use ribbon cable for
RS-232 connections.

Modulation CCITT V.22bis, 2400 bit/s

CCITT V.22, Bell 212A, 1200 bit/s
CCITT V.21, Bell 103, 300 bit/s

CCITT V.23, 1200/75 bit/s & 1200 Hdx
Dial up Tone signals DTMF
Settings AT-commands & switches
Transmission Asynchronous & Synchronous
Transmission speed, DTE 300, 600, 1200, 2400, 9600, 19200 bit/s
Compression V.42bis & MNP5 (Not leased Line)
Characters up to 11 bits
Error correction V.42, MNP 2-4 & MNP 10 (Not leased line)
Interface EIA RS-232-C/V.24/V.28
Line interface RJ12 or 4-pole screw connector
Line 2-wire for dial up connections

2- or 4-wire for leased line connections
REN, Ringer Equivalence Number 1
Power 230 VAC -10% +15%, 48-62 Hz (TD-22 AC)

12-36 VDC (TD-22 DC)

115 VAC or 36-60 VDC can be delivered as optional
Power consumption 25 mA at 230 VAC

200 mA at 12 VDC
Isolation Between line, RS-232 connection and power 1500V.
Temperature/humidity 5-50°C surrounding temperature

0-95% RH, without condensation

Extended temperature can be delivered as an option
0-95% RH, without condensation Extended temperature can be delivered as an option
Size, mm (W*H*D) 55 * 100 * 128
Weight, kg 0.6 (TD-22 AC) & 0.4 (TD-22 DC)
Indications PWR, LINE, ANS, REL, TD, RD, RTS, DCD, DTR & DSR

Light emitting

diodes

Screw-block
for RS-232
connection

25-pole D-sub
for RS-232
connection

PWR
connection

Line connection

RJ-12

Line connection

screw block

▼

▼

▼

▼

▼▼

25 Pin Screw Direction Name Description
D-sub Terminal DCE-DTE

1 - - - PE Protective earth
2 8 TXD Transmit data
3 7 RXD Receive data
4 6 RTS Request to send
5 5 CTS Clear to send
6 2 DSR Modem ready
7 1 - - - SG Signal ground
8 4 DCD Data carrier detect

9 Continuous high
10 Continuous low
12 DRS Speed indication (1200/2400)
15 TXC Synchronous TXD clock from modem
17 RXC Synchronous RXD clock from modem
20 3 DTR Data terminal ready
21 RDL Request of remote digital loopback
22 9 RI Ring indicator
23 DRS Data speed select (1200/2400)
24 EXC External synchronous clock
25 TI Test indication signal

6 6177-2203

RS-232 Connections

Pin outs for the 25-pole D-sub and 9-pole screw terminal:

The other pins in the 25-pole D-sub should be left unconnected.

Line connection

The telephone line is connected to the 6-pole RJ-12
connector or to the 4-pole screw block in the bottom
left side.
When using the screw-block a strap plug supplied must
be placed in the RJ-12 connector. If this is not done the
outgoing signal will not be connected to the screw­block.

←
←

←
←

←
←

←
←

←
←

←
←

←

←

←
←
←

1
:
6

1 2 3 4

2-wire lines are connected to the two middle pins
(3 & 4) in the RJ-12 plug or the TX screws
(1 & 2).
In the UK modems the RJ-12 connection is on pin
2 & 5.
4-wire lines are connected to the screw terminal,
transmitter to TX (1 & 2) and receiver to RX (3 & 4).

76177-2203

Typical TD-22 line connections

4-position
screw-terminal

Handshaking

Leased line 2-wire

Telephone
exchange

Telephone
exchange

Dial up line 2-wire

Telephone modem

4-position
screw-terminal

4-position

screw-terminal

RJ-12 connector

Leased line 4-wire

Telephone
exchange

Telephone
exchange

Dial up line 2-wire

Telephone modem

1234567

8

9

The TD-22 is delivered with a factory setting for ”hardware hand­shake” with RTS-CTS which means that if only TX, RX and GND
are connected no data will be sent on the receiving modem’s RS-232
connection unless RTS is high. The problem can be solved by placing
a jumper between RTS (screw terminal no 6) and for example DSR
(screw terminal no 2) or by disabling the handshake with the command
AT&K0.

3
4

8 6177-2203

DIP Switch Setup

Disconnect power before changing DIP-switches.

Take ESD-protection when changing switches.

The DIP-switches can be used to provide the following settings.
The DIP-switches are underneath the top lid of the modem. (1 = On, 0 = Off)
Non defined switches will be in off position.

SW1:

4321

0 Dial-up line
1 0 Leased line, switch off echo and result code. Answering
1 1 Leased line, switch off echo and result code. Dialling.

1 All commands ignored, including +++

SW2:

8765 4321

0 SW2:2 to 7 not used
1 For use of SW2:2 to 7

Choice of clock: Clock source:
0 0 Asynchronous
0 1 Synchronous Ext. Clock from D-sub pin 24
1 0 Synchronous Int. The modem creates clock
1 1 Synchronous slave Clock from line

1 DTR/DSR disconnected (AT&S0&D0&C0)

1 V.25 commands enabled

1 Remote configuration enabled

1 Callback security enabled

8765 4321

0 4-wire line connection
1 2-wire line connection

0

1 REL-mode disconnected

SW3:

96177-2203

SW4:

87654321Select speed and parity towards

computer/terminal
0 0 0 0 Automatic speed and format setting up
0 0 0 1 300 Baud
0 0 1 0 600 Baud
0 0 1 1 1200 Baud
0 1 0 0 2400 Baud
0 1 0 1 4800 Baud
0 1 1 0 9600 Baud
0 1 1 1 19200 Baud

0 0 0 7,N
0 0 1 7,E
0 1 0 7,O
0 1 1 8,N
1 0 0 8,E
1 0 1 8,O
1 1 0 8,O* Sets direct-mode AT&Q0

(Used for 8 bits, optional parity)

1 1 1 8,N* Sets direct-mode AT&Q0

(Used for 7 bits, optional parity)

1 2-stop bits

*) The modem use this format when sending information to the DTE only in command mode.

10 6177-2203

8765321Select Line Modulation

0 0 0 Use saved parameters
0 0 1 V.21 300 bps (0-300) ATF1
0 1 0 V.23 Hdx ATF3 %F3
0 1 1 V.23 1200/75 bps ATF3
1 0 0 V.22 1200 bps ATF4
1 0 1 V.22 bis 2400 bps ATF5
1 1 1 Auto-detect mode ATF0

SW5:

116177-2203

LED Status Indicators

PWR: Full Intensity The modem is functioning normally

Half intensity The modem is in test mode or remote

configuration mode
Occasional flashing with speaker click Power supply problem
1:6, on:off ratio RAM error
On/off with speaker click Modem unable to start

LINE LED lights up when the modem has the line
ANS LED flashes when a ring is detected on the line. The ANS indicator shines constantly

when answering an incoming call and remains lit thereafter to indicate the modem is
in autoanswer mode.

REL When the modem is in error correcting and compressing mode this LED is on.When

the modem is in direct or normal mode this LED remains off.

TD Transmitted Data: Shows data received from the local RS-232 port
RD Received Data: Shows data leaving the modem on the RS-232 port
RTS Request to Send signal from the DTE
DCD Data Carrier Detect modem signal
DSR Data Set Ready modem signal

Please also refer to AT&C, AT\N, AT&T, ATS0

12 6177-2203

DTE Command Lines

A command line is a string of characters sent from a DTE to the modem (DCE) while the modem is
in a command state. Acommand line has a prefix, a body, and a terminator. Each command line
(with the exception of the A/ command) must begin with the character sequence AT and must be
terminated by a carriage return. Commands entered in upper case or lower case are accepted, but
both the Aand T must be of the same case, i.e., ”AT” = ASCII 065, 084 or ”at” = ASCII 097, 116.

The body is a string of commands restricted to printable ASCII characters (032 – 126). Space
characters (ASCII 032) and control characters other than CR (ASCII 013) and BS (ASCII 008) in the
command string are ignored. The default terminator is the ASCII <CR> character. Characters that
precede the AT prefix are ignored. The command line interpretation begins upon receipt of the
carriage return character.
Characters within the command line are parsed as commands with associated parameter values. The
basic commands consist of single ASCII characters, or single characters preceded by a prefix character
e.g., & or % or \ or ) followed by a decimal parameter. Missing decimal parameters are evaluated as 0.

The modem supports the editing of command lines by recognising a backspace character. When
modem echo is enabled, the modem responds to receipt of a backspace or delete by echoing a
backspace character, a space character, and another backspace. The hex value to be used for the
backspace character is programmable through register S5. Values equal to 0 or greater than 127, or
the value which corresponds to the carriage return character, cannot be used for the backspace
character. This editing is not applicable to the AT header of a command. Acommand line may be
aborted at any time by entering < ctrl-x > (18h).
The AT sequence may be followed by any number of commands in sequence, except for commands
such as Z, D, or A. Commands following commands Z, D, or A on the same command line will be
ignored. The maximum number of characters on any command line is 39 (including ”A” and ”T”). If
a syntax error is found anywhere in a command line command, the remainder of the line will be
ignored and the ERROR result code will be returned.
Most commands entered with parameters out of range will not be accepted and the ERROR response
will be returned to the DTE.

Commands will only be accepted by the modem once the previous command has been fully
executed, which is normally indicated by the return of an appropriate result code. Execution of
commands D and A, either as a result of a direct command or a re-execute command, will be aborted
if another character is entered before completion of the handshake.

When the modem has established a connection and has entered on-line data mode, it is possible to
break into the data transmission in order to issue further commands to the modem in an on-line
command mode. This is achieved by the DTE sending to the modem a sequence of three ASCII
characters specified by register S2. The default character is ‘+’. The timing of the three characters
must comply with specific time constraints. There is a guard time before the first character (the pre­sequence time), a guard time following the third character (the post-sequence time), and a guard
time-out between the first and second characters and between the second and third characters (the
inter-character time). These times are controlled by the value recorded in register S12.

136177-2203

AT COMMAND SET

The modem will respond to the commands detailed below. Parameters applicable to each command
are listed with the command description.

A/ – Re-execute Command

The modem behaves as though the last command line had been re-sent by the DTE. ”A/” will repeat
all the commands in the command buffer.
The principal application of this command is to place another call (using the Dial command) that
failed to connect due to a busy line, no answer, or a wrong number. This command must appear alone
on a command line. This command should not be terminated by a carriage return.

A – Answer

The modem will go off-hook and attempt to answer an incoming call if correct conditions are met.
Upon successful completion of answer handshake, the modem will go on-line in answer mode. This
command may be affected by the state of Line Current Sense, if enabled. (Most countries do not
require Line Current Sense.) Operation is also dependent upon country-specific requirements.

Please also refer to ATDn, S0, S1, S7, S8, S9 and S30.

\An – Select Maximum MNP Block Size

The modem will operate an MNP error corrected link using a maximum block size controlled by the
parameter supplied. The parameter value, if valid, is written to S40 bits 6 and 7.

\A0 64 characters.
\A1 128 characters.
\A2 192 characters. (Default.)
\A3 256 characters.

Please also refer to AT\N

&An – Dial Abort Option

The modem normally aborts the connection negotiation if a character is received from DTE during
the connection phase. This command give the user the option to let the modem ignore incoming
characters.

&A0 Enable abort. (Default.)
&A1 Disable abort.

Please also refer to AT&D

Bn – CCITT or Bell

When the modem is configured to allow either option, the modem will select Bell (American
standard) or CCITT (European standard) modulation for a line speed connection of 300 or 1200 bps
according to the parameter supplied. Any other line speed will use a CCITT modulation standard.

B0 Selects CCITT operation at 300 or 1200 bps. (Default.)
B1 Selects BELL operation at 300 or 1200 bps

Please also refer to ATFn, S27

14 6177-2203

&Bn – DTR Dial Option

This command interprets the OFF to ON transition of the DTR signal from the DTE to enable the

modem to dial the telephone number stored with ATZ0=...... The parameter value, if valid, is written

to S27 bits 7.
&B0 No action. (Default.)

&B1 Dial on OFF to ON transition of the DTR signal.

Please also refer to AT&Z and AT&D.

\Bn – Transmit Break to Remote

In non-error correction mode, the modem will transmit a break signal to the remote modem with a
length in multiples of 100 ms according to parameter specified. If a number in excess of 9 is entered,
9 is used. The command works in conjunction with the \K command.
In error correction mode, the modem will signal a break through the active error correction protocol,
giving no indication of the length.

\B1-\B9 Break length in 100 ms units. (Default = 3.)

Note: When the modem receives a break from the remote modem, break is passed to the DTE as
follows: In non-error correction mode direct, the break length is passed; in non-error correction mode
normal and in error correction mode, a 300 ms break is passed.

&Cn – DCD Option

The modem controls the DCD output in accordance with the parameter supplied. The parameter
value, if valid, is written to S21 bit 5.
On leased line DCD always follows the state of the carrier.

&C0 DCD remains ON at all times. (Default.)
&C1 DCD follows the state of the carrier.

%C – Enable/Disable Data Compression

Enables or disables data compression negotiation. The modem can only perform data compression on
an error corrected link. The parameter value, if valid, is written to S41 bits 0, 1 and S46 bit 1.

%C0 Disables data compression.
%C1 Enables MNP 5 data compression negotiation.
%C2 Enables V.42 bis data compression.
%C3 Enables both V.42 bis and MNP 5 data compression. (Default)

Please also refer to AT\Nn.

*Cn – Password for remote control

This command directs the modem to ask for a password, ”ENTER PASSWORD”. In order to execute
remote configuration the calling modem will have to present the password before making any
editing. The password must consist of between 6 and 12 letters. The default setting is ”QWERTY”.
This command is available only for MNP connections.

Please also refer to AT\Nn, AT*E and AT*R.
Not available in remote programming mode (AT*R)

156177-2203

Dn – Dial

This command directs the modem to go on-line, dial according to the string entered and attempt to
establish a connection. If no dial string is supplied, the modem will go on-line and attempt the
handshake in originate mode.
Dial Modifiers.

The valid dial string parameters are described below.

0-9 DTMF digits 0 to 9.
* The 'star' digit (tone dialling only).
# The 'gate' digit (tone dialling only).
A-D DTMF digits A, B, C, and D. Some countries may prohibit sending of these digits

during dialling.

J Perform MNP 10 link negotiation at the highest supported speed (for this call only).

(also refer to AT*H)

K Enable power level adjustment during MNP 10 link negotiation (for this call only).

(also refer to ATMn)

L Re-dial last number: the modem will re-dial the last valid telephone number. The L

must be immediately after the D with all the following characters ignored.
P Select pulse dialling. In most countries is this not available
T Select tone dialling (DTMF) tone dialling is normally used in this modem.
S=n Dial the number stored in the directory (n = 0 to 3 or 0 to 19 depending on the modem

model). (See &Z.)
W Wait for dial tone: the modem will wait for dial tone before dialling the digits

following ”W”. If dial tone is not detected within the time specified by S6 the modem

will abort the rest of the sequence, return on-hook, and generate an error message.
, Dial pause: the modem will pause for a time specified by S8 before dialling the digits

following ”,”.
; Return to command state. Added to the end of a dial string, this causes the modem to

return to the command state after it processes the portion of the dial string preceding

the ”;”. This allows the user to issue additional AT commands while remaining off-

hook. The additional AT commands may be placed in the original command line

following the ”;” and/or may be entered on subsequent command lines. The modem

will enter call progress only after an additional dial command is issued without the ”;”

terminator. Use ”H” to abort the dial in progress, and go back on-hook.
^ Toggles calling tone enable/disable: applicable to current dial attempt only.
(-),<space> Ignored: may be used to format the dial string.

If the ATD.. command returns ERROR the ATX0 is probably set in a country that does not allow
blind dialling.

Please also refer to ATA, ATX, AT&Z, S6, S7, S8, S9, S30.

16 6177-2203

&Dn – DTR Option

This command interprets the ON to OFF transition of the DTR signal from the DTE in accordance
with the parameter supplied. The parameter value, if valid, is written to S21 bits 3 and 4.

&D0 DTR drop is interpreted according to the setting as follows: (Default.)

&Q0, &Q5 or &Q6

DTR is ignored (assumed ON). Allows operation with DTEs which do
not provide DTR.

&Q1 or &Q4

DTR drop causes the modem to hang up.

&Q2 or &Q3

DTR drop causes the modem to hang up. Auto-answer goes off.

&D1 DTR drop is interpreted according to the setting as follows:

&Q0, &Q1, &Q4, &Q5 or &Q6

The modem returns to command state without disconnecting.

&Q2 or &Q3

DTR drop causes the modem to hang up. Auto-answer goes off.

&D2 DTR drop causes the modem to hang up. Auto-answer is inhibited.

&D3 DTR drop is interpreted according to the setting as follows:

&Q0, &Q1, &Q4, &Q5 or &Q6

DTR drop causes the modem to perform a soft reset as if the Z command were
received. The &Y setting determines which profile is loaded.

&Q2 or &Q3

DTR drop causes the modem to hang up. Auto-answer goes off.

Please also refer to AT&M, AT&Q, S21.

%D0 Disconnect the connection at a signal level below -43dBm. (Default.)
%D1 Disconnect the connection at a signal level below the value stored in S24.

Please also refer to S24

En – Command Echo

The modem enables or disables the echo of characters to the DTE according to the parameter
supplied. The parameter value, if valid, is written to S14 bit 1.

E0 Disables command echo.
E1 Enables command echo. (Default.)

Please also refer to ATQ

176177-2203

%En – Enable/Disable Line Quality Monitor and Auto­Retrain or Fallback/Fall Forward (V.22bis only)

Controls whether or not the modem will automatically monitor the line quality and request a retrain
(%E1) or fall back when line quality is insufficient or fall forward when line quality is sufficient
(%E2). The parameter value, if valid, is written to S41 bits 2 and 6.
If enabled, the modem attempts to retrain for a maximum of 30 seconds.

%E0 Disable line quality monitor and auto-retrain.
%E1 Enable line quality monitor and auto-retrain (default).

Please also refer to ATO

*E – Exit Remote configuration mode

Upon receipt of this command from the telephone line, the modem will exit remote configuration
mode and transmit the OK result code to the line.Please also refer to S202.

Fn – Select Line Modulation

This command selects the line modulation according to the parameter supplied. The line modulation
is fixed unless Automode is selected. This command interacts with the S37 and the N command. The
parameter value, if valid, is written to S37 bits 0-4. To select line modulation it is recommended that
either the F command, or a combination of the S37 and the N command are used but not both.

F0 Selects auto-detect mode. Sets N1 and sets S31 bit 1. In this mode, the modem

configures for Automode operation. All connect speeds supported by the modem are

possible according to the remote modem's preference. The contents of S37 are ignored

as is the sensed DTE speed.
F1 Selects V.21 or Bell 103 according to the B setting as the only acceptable line speed

resulting in a subsequent connection. Sets N0, sets S37 to 1, and clears S31 bit 1.

This command is equivalent to the command string: ATN0S37=1.
F2 Not supported.
F3 Selects V.23 as the only acceptable line modulation for a subsequent connection.

Originator is at 75 bps and answer is at 1200 bps. Sets N0, sets S37 to 7, and clears

S31 bit 1. This command is equivalent to the command string: ATN0S37=7.
F4 Selects V.22 1200 or Bell 212A according to the B command setting as the only

acceptable line speed for a subsequent connection. Sets N0, sets S37 to 5, and clears

S31 bit 1. This command is equivalent to the command string: ATN0S37=5.
F5 Selects V.22 bis as the only acceptable line modulation for a subsequent connection.

Sets N0, sets S37 to 6, and clears S31 bit 1. This command is equivalent to the

command string: ATN0S37=6.

Please also refer to ATN, ATB, S37

&F – Recall (restore) factory configuration

This command restores the original factory setting of all parameters. The factory defaults are
identified for each command and in the S-register descriptions. When the modem is restarted the
parameters set by the customer will be restored. By using the &W command the factory settings will
be valid also after restart of the modem.