ABB 1MRS119000 User manual

1MRS119000
Plug-in Modem
Operator´s manual

2
1MRS 750577-MUM EN
Issued 98-06-02
Version A
Checked MKa
Approved OV
Data subject to change without notice
1MRS119000
Plug-in Modem
Contents
1.0 General ......................................................................................................... 4
1.1 Introduction ......................................................................................... 4
1.2 Type marking ........................................................................................ 5
1.3 Features ................................................................................................. 5
1.4 Technical specifications ......................................................................... 6
1.4.1 LED indicator functions .............................................................. 6
1.4.2 Interface connectors ..................................................................... 6
1.4.3 Telephone line interface ............................................................... 6
1.4.4 Private line ................................................................................... 6
1.4.5 Radio interface ............................................................................. 7
1.4.6 DTE ............................................................................................ 7
1.4.7 Power consumption ..................................................................... 7
1.4.8 Environmental conditions............................................................ 7
1.4.9 Mechanical dimension ................................................................. 7
1.5 Block diagram ....................................................................................... 8
1.6 Power supply and booting ..................................................................... 9
1.7 LED indicators ..................................................................................... 9
1.8 On board controls ................................................................................. 9
1.9 Loudspeaker .......................................................................................... 9
2.0 Installation and connection ......................................................................... 10
2.1 Introduction ....................................................................................... 10
2.2 Connectors ......................................................................................... 11
2.3 Jumpers ............................................................................................... 12
2.4 Phone line connections ....................................................................... 12
2.5 Radio connections............................................................................... 12
2.6 Leased and fixed Line connections ...................................................... 12
2.7 Connection examples .......................................................................... 13
2.8 Common configuration strings ........................................................... 13
2.9 DTE connection ................................................................................. 14
2.10 Mounting............................................................................................ 14
2.11 Powering-up ........................................................................................ 14

3
3.0 Command overview .................................................................................... 15
3.1 Introduction ....................................................................................... 15
3.2 Command syntax ................................................................................ 15
3.2.1 DTE Commands ....................................................................... 15
3.2.2 AT Command guidelines ........................................................... 15
3.2.3 Basic command syntax ............................................................... 15
3.3 AT Command ..................................................................................... 15
3.3.1 AT Command guidelines ........................................................... 15
3.3.2 AT Commands, DTE Adaptation .............................................. 15
3.3.3 AT Command Format ............................................................... 16
3.3.4 Escape Code Sequence ............................................................... 16
3.4 AT Commands ................................................................................... 17
3.4.1 AT& Commands ....................................................................... 26
3.4.2 AT% Commands ....................................................................... 30
3.4.3 AT\ Commands ......................................................................... 30
3.5 Error detection and data compression commands ............................... 31
3.5.1 AT% Commands ....................................................................... 31
3.6 Special commands............................................................................... 31
3.7 AT Command Result Codes ............................................................... 32
3.8 S Registers ........................................................................................... 37
3.8.1 Factory defaults .......................................................................... 37
4.0 AT command set summary ......................................................................... 39
5.0 Service ......................................................................................................... 42
6.0 Trouble-Shooting ........................................................................................ 42

4
1.0 General
1.1 Introduction
The 1MRS119000 modem board is a multifunctional plug-in modem board which can be
used together with several distribution automation products of ABB Transmit Oy. Via the
local public telephone network or leased lines the modem provides data communication at
up to 14400 bps. Furthermore, the modem can be connected to several types of radios for
communication via a radio-operated network.
This optional modem board is used for communication between aremotely contrlled unit or
a protection relay and a host computer. It is only delivered as part of such systems. The
modem board takes care of the data communication from station-level equipment to the host
computer via a public telephone network, leased lines or a conventional radio network.
The modem is designed according to the following international ITU-T recommenda-
tions for data signalling rates up to 14400 bps:
ITU-T V.21 300 bps
ITU-T V.22 1200 bps
ITU-T V.22bis 2400 bps
ITU-T V.23 1200/75 bps
ITU-T V.32 4800/9600 bps
ITU-T V.32bis 14400 bps
The line interface fulfils the NET 4 (ETS 300 001, second edition, April 1994) specifica-
tion for the agreed countries: "Attachments to Public Switched Telephone Network (PSTN);
General technical requirements for equipment connected to an analog subscriber interface
in the PSTN".
The AT command set is used for configuration of both the telephone modem and the
radio modem. Configuration is done via the RS 232 serial interface with help of a PC/
Terminal (DTE).
The remote configuration of the modem offers users network management capabilities.
The user can configure the modem at remote sites from local modems, without having to
visit the local stations or rely on the service personnel to follow instructions.

5
1.2 Type marking
The type marking of the modem consists of a type number, a temperature range code and
a country code. The type number is 1MRS119000-_ _ _. The one-letter temperature range
code and the two-letter country code specify the service temperature range and the desti-
nation country where the modem is to be installed. The country code is needed to make
sure that the public line part of the modem has been approved for use in the destination
country. The status of approval per country can be inquired from ABB Transmit Oy or
ABB's local customer centre.
Example of the type marking:
1MRS119000 -AFI
|||
| | Country code FI = Finland
||
| Temperature range A = +5…+50°C
| B = -20…+60°C
Type number
Country codes are:
AR = Argentina AT = Austria AU = Australia BE = Belgium
BR = Brazil CA = Canada CH = Switzerland CO = Colombia
CZ = Czech republic DE = Germany DK = Denmark EE = Estonia
EG = Egypt ES = Spain FI = Finland GB = Great Britain
GR = Greece HK = Hong Kong HU = Hungary ID = Indonesia
IE = Ireland IL = Israel ID = Indonesia IT = Italy
MX = Mexico MY = Malaysia NL = Netherlands NO = Norway
NZ = New Zealand PH = Philippines PL = Poland PT = Portugal
SA = Saudi Arabia SE = Sweden SG = Singapore SI = Slovenia
TR = Turkey TW = Taiwan RU = Russia VE = Venezuela
ZA = South Africa
1.3 Features
DTE Interface: an RS232 serial interface with hardware handshaking, connected to two 9-
pin female D-connectors.
Line interface: a transformer-coupled telephone line interface with tone and pulse dialling.
The line interface can be used in both 2-wire and 4-wire dial-up and leased line connec-
tions.
Radio interface: a combined interface for connecting either a leased line, or a radio trans-
ceiver.
Both the Line interface and Radio interface can be used for communication over leased
lines.
Indication LEDs: The seven LEDs show the operation status of the modem.
Designed for operation in distribution automation environment.

6
1.4 Technical specifications
1.4.1 LED indicator functions
Total 7 LEDs:
LIN Modem connected to line (off hook), Green
connected to line relay control signals
RNG Indicates a true ringing signal Green
TXD Transmitted data. Connected to the modem TxD signal Green
RXD Received data. Connected to the modem RxD signal. Green
CD Carrier detect. Green
RTS Request to send. Green
IRF Internal Fault detected by the watchdog. Normally off. Red
1.4.2 Interface connectors
Connector Type Function
X1 64-pin Euro power supply
X2 9-pin D-connector RS 232 serial interface
Xn.1 RJ12 public telephone network
Xn.2 9-pin D-connector RS 232 serial interface
Xn.3 10-pin leased line / radio
Loudspeaker on-board, adjustable sound volume
1.4.3 Telephone line interface
Modes Dial up, 2-or 4- wire leased or fixed line, Xn.1/1-6
ITU-T recommendations:
ITU-T V.21 300 bps
ITU-T V.22 1200 bps
ITU-T V.22bis 2400 bps
ITU-T V.23 1200/75 bps
ITU-T V.32 4800/9600 bps
ITU-T V.32bis 14400 bps
1.4.4 Private line
Input sensitivity -43 to dBm, Xn.3/1-2 or 3-4.
Output level software adjustable, -2 to -17 dBm, Xn.3/1-2.
Modem configuration AT commands and S registers, Jumper settings

7
1.4.5 Radio interface
Modes Radio, 2- or 4-wire private line
Input sensitivity -43 dBm, Xn.3/1-2 or 3-4.
Output level software/automatic adjustable,-2 dBm ... -17 dBm, Xn.3/1-2.
Subcarrier detector 12 - 60 V forward voltage, 0.3 - 1.8 mA.
6 V maximum backward voltage. Xn.3/9-10.
TX/RX switch (PTT) relay operated (5 A, 30 Vdc, 250 Vac), Xn.3/6-8.
TX/RX delay adjustable between 30 and 2000 ms
Modem configuration AT commands and S registers
1.4.6 DTE
Interface 2 x RS232 in parallel, X2 and Xn.2.
Data speed Auto detection between 300 - 38 400 bit/s
Data format Auto detection between:
7 or 8 data bits
odd, even or no parity
1 stop bit
1.4.7 Power consumption
5 V typical 165 mA, max 250 mA
24 V passive typical 26 mA, active typical 45 mA, max. 60 mA
1.4.8 Environmental conditions
Ambient temperature range
- normal +5…+50°C
- extended -20…+60°C
Storage temperature range -40…+125°C
Relative humidity 15…90%, non-condensing
1.4.9 Mechanical dimension
Size 160 x 233.4 mm (E2), component high max 16 mm.
The modem is approved and manufactured by Westermo Teleindustri AB,
640 40 Stora Sundby, Sweden.

8
1.5 Block diagram
SERIAL
INTERFACE
INDICATOR
CIRCUIT
MICRO
CONTROLLER
MODEM
DATA
PUMP
MCU
CRYSTAL
EEPROM RESET
CIRCUIT
LINE
INTERFACE
MDP
CRYSTAL
SPEAKER
CIRCUIT
EPROM SRAM
Fig. 1. Block diagram

9
1.6 Power supply and booting
The plug-in modem board is an optional unit for ABB Transmit Oy protection and con-
trol products. The modem is powered by the equipment it is used in and does not need a
separate external power supply.
Modem settings are stored in non-volatile memory on the modem board and read after
powering up. For certain settings, the microcontroller to which the modem is connected,
sends initialisation strings after power-up of the unit.
The supply voltages are: +5Vdc ±2% / 165 mA for the electronics
+24Vdc ±10% / 45 mA for the relays and LEDs
1.7 LED indicators
Communication to and from the modem, as well as the modem operation status can be
checked with help of seven diagnostic LED indicators.
The LED indicators are:
LIN Modem connected to line (off hook), Green
connected to the line relay control signals
RNG Indicates a true ringing signal. Green
TXD Transmitted data. Connected to the modem TxD signal Green
RXD Received data. Connected to the modem RxD signal. Green
CD Carrier detect. Green
RTS Request to send. Green
IRF Internal Fault detected by the watchdog. Normally this LED is off. Red
1.8 On-board controls
The 1MRS119000 is designed on a single printed circuit board (PCB). The board con-
tains 11 series of jumpers for country-specific settings. The jumpers can only be reached
after removing the PC board from the rack it normally is mounted in.
The jumpers are not allowed to change by users because of country-specific rules and
approvals.
1.9 Loudspeaker
An on-board piezoelectric loudspeaker is provided, mainly for testing purposes. For nor-
mal, silent operation, the loudspeaker can be switched off, or set to a low volume by alter-
ing certain settings. Refer to the chapter ‘Command Overview’.

10
2.0 Installation and connection
2.1 Introduction
The installation of the 1MRS119000 consists mainly of making the physical connections
between the modem and the telephone network, leased line, fixed lines or radio equip-
ment. The power supply connection and the connection for data transfer to and from the
microcontroller (protective relay, I/O unit) are made after the modem board has been
properly inserted. Mounting of the modem board is described in the manual of the equip-
ment it is part of. A separate connector is provided to connect the modem to a PC using a
standard RS232 cable. This connector is only used for setting up the modem and for
service. Setting up the modem can also be done remotely.
Installation procedure:
1. Insert the PC board properly into the rack. As the modem board normally is ordered as
part of other distribution automation equipment, this is done by the factory.
2. Connect the modem to the dial-up lines, leased line or radio equipment. For setting up
the modem, connect a PC temporarily to the modem board.
3. Attach the auxiliary supply and check the operation of the modem with help of the LED
indicators.
4. Verify that the modem settings are in conformance with the network configuration and
match with the settings of the modem used at the host computer. Check for error cor-
rection, baud rate, data compression, etc. See the chapter ‘Command overview’ for a
detailed description on the available modem commands.
5. Verify self-test results. See chapter ‘Self-test’.
6. Check the modems operation in the network.

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2.2 Connectors
All connectors are directly mounted on the modem board. The connector name, type of
connectors and their functions are as follows:
Connector Type Function
X1 64-pin Euro power supply
X2 9-pin D-connector RS 232 serial interface
Xn.1 RJ12 public telephone network
Xn.2 9-pin D-connector RS 232 serial interface
Xn.3 10-pin leased line / radio
n is the card slot number for the modem board.
Connectors X2 and Xn.3 are connected in parallel. For a description of the pin configura-
tion of each connector, refer to chapter ‘Technical Specifications’.
LED indicators
LIN Modem connected to line (off hook), connected to the line relay control signals
RNG Indicates a true ringingsignal, connected to the micro controller
TXD Tranmitted data, connected to modem's TxD-signal
RDX Received data, connected to modem's RxD-signal
CD Carrier detect, connected to the micro controller
RTS Ready To Send, connected to the micro controller
IRF Internal Fault detected by the watchdog. Led is normally off.
Xn.1, RJ-12 Telephone line
Xn.2, RS-232 connector
Xn.3, radio and leased line connector
1 TX_LINEA, 2-wire connection and 4-wire transmit.
2 TX_LINEB, 2-wire connection and 4-wire transmit.
3 RX_LINEA, 4-wire receive data.
4 RX_LINEB, 4-wire receive data.
5 Not connected
6 RADIO_ONA, Radio ON relay, normally open contact.
7 RADIO_ONC, Radio ON relay, common.
8 RADIO_ONB, Radio ON relay, normally closed contact.
9 SCUELCH STATEA, Radio subscriber detect (+).
10 SCUELCH STATEB, Radio subscriber detect (–).
Pin Signal V.24 I/O Description
1 DCD 109 O Data Carrier Detect
2 RxD 104 O Received data
3 TxD 103 I Transmitted data
4 DTR 108/2 I Data Terminal Ready
5 GND 102 - Signal ground
6 DSR 107 O Data Set Ready
7 RTS 105 I Request TO Send
8 CTS 106 O Clear TO Send
9 RI 125 O Ring Indicate
Fig. 2. Connection view
As the cables to be used for connecting the modem to the telephone network, leased lines
and radio system depend on local conditions, these are not provided. For connecting a PC
to the modem, use a standard RS232.

12
2.3 Jumpers
The jumper settings are for country-specific parameters. They should normally not be
changed after delivery of the modem.
2.4 Phone line connections
The 1MRS119000 modem is designed for communications over a Public Switched Net-
work Telephone line.
Connection to the phone system is made via an RJ12 type jack (connector Xn.1). Depend-
ing on the function of the line, the modem will be connected through one or several line
relays. It can be connected to a switched or leased line network, 2-wire or 4-wire trans-
former coupled line interface and a ring detector opto.
Cables for connecting the modem board to the dial-up lines or leased lines are not pro-
vided as the type of cable and attached connector depend on the application. Refer to the
technical specifications and pin configurations for attaching the 1MRS119000 modem
board to the available lines.
2.5 Radio connections
The interface connector Xn.3 is used for connecting the 1MRS119000 modem board to
either a leased line or a suitable radio transceiver. For the use of radio equipment extra I/O
signals are provided: output relay contacts for switching between send and receive and a
receiver subcarrier detection input.
The connection to a radio transceiver strongly depends on the type of radio used. It should
be noted that only certain types of radio transceivers are suitable for the transmission of
high speed digital data. For attaching the radio transceiver to the modem board, refer to
the documentation provided with the radio equipment and refer to the pin configuration
of connector Xn.3 given in chapter ‘Technical Specifications’.
Cables for connecting the modem-board to the radio equipment are not provided as the type
of cable and attached connectors depend on the application and the type of radio used.
Always refer to the technical specifications and pin configurations for attaching the
1MRS119000 modem board to external devices.
2.6 Leased and fixed Line connections
Both the phone line and the radio interface can be used for attaching a leased line. In many
applications in distribution automation, leased lines, also called dedicated or private lines,
are used. The 1MRS119000 modem is designed for use over a 2-wire or 4-wire leased line.
No special line conditions are needed and the operation is full-duplex. The leased lines can
be connected to the phone line interface connector (Xn.1, see previous section) or to the
radio interface connector Xn.3.
Cables for connecting the modem board to leased lines are not provided as the type of
cable and attached connectors depend on the application.
Always refer to the technical specifications and pin configurations for attaching the
1MRS119000 modem board to external devices.

13
2.7 Connection examples
2.8 Common configuration strings
Mode Connector Initialisation string originate Answer
Dial up: Xn.1 AT&FDnnnn AT&FS0=1
2-wire fixed line Xn.1 AT&F&L1D AT&F&L1A
2-wire fixed line Xn.3 AT&F&L1&J1D AT&F&L1&J1A
4-wire fixed line Xn.1 AT&F&L1&H1D AT&F&L1&H1A
4-wire fixed line Xn.3 AT&F&L1&J1&H1D AT&F&L1&J1&H1A
4-wire radio V.23 HDX Xn.3 AT&F&E1%F3&L1&J1&H1D AT&F&E1%F3&L1&J1&H1A
AT &F Set factory default,
Dnnnn Dial number nnnn
S0=1 Auto answer after 1 ring signal
&L1 Fixed line synchronisation enabled
&L0 Normal dial-up connection
D Set modem as originate
A Set modem as answering
&J1 Set line to radio screw connector
&J0 Set line to telephone connector
&H1 4-wire line
&H0 2-wire line
&E1 Radio subcarrier control enabled
&E0 Radio subcarrier control disabled
%F3 Set V23 half duplex 1200/1200
Key in the telephone number instead of nnnn
1MRS119000 1MRS119000
TX/RX_LINE
TX/RX_LINE
TX/RX_LINE
TX/RX_LINE
1MRS119000
1MRS119000
1MRS119000 RADIO
TX_LINE
TX_LINE TX_LINE
TX_LINE
RX_LINE
RX_LINE RX_LINE
RX_LINE
TX_LINE
TX_LINE TX_LINE
TX_LINE
RX_LINE
RX_LINE RX_LINE
RX_LINE
RADIO_ON
RADIO_ON
Transmitter
Scuelch
detect
+
SCUELCH_STAT
SCUELCH_STAT
2-wire leased line
4-wire leased line
Radio

14
2.9 DTE connection
During commissioning, all settings to the modem board 1MRS119000 are made using a
DTE (terminal or Personal Computer running e.g. a terminal emulation program). The
DTE is to be connected to the 9-pin female connector Xn.2 via a standard RS 232 cable. If
you use your own cable, always check that the cable matches the pin configuration of the
modem board and DTE. Refer to the technical specifications for further details.
Connector Xn.2 has the same functionality as connector X2 on the rear side of the modem
board. Connector X2 is used for the data communication between the modem and the
microcontroller of the distribution automation equipment in which the modem is used.
The two serial interface connectors can only be used one at the time. The modem board
has a built-in serial interface using the data formats from: 1 start bit, 7 data bits, no parity
and 1 stop bit, up to: 1 start bit, 8 data bits, 1 parity and 1 stop bit.
The modem recognises the DTE data format (baud rate, number of data bits, etc.) auto-
matically after typing AT followed by a <CR> (carriage return), as long as the DTE data
formats are within the above mentioned range. Preferably, the DTE data formats should be
the same as the communication settings of the secondary substation equipment in which
the modem is used. The communication between the modem and the DTE is always half
duplex.
2.10 Mounting
The modem board is only delivered as part of ABB Transmit Oy's secondary substation
equipment and is therefore mounted by the factory. For altering jumper settings and for
service reasons, the modem board might have to be removed from the rack in which it is
normally mounted. The position of the modem board in the rack is described in the manu-
als of the concerned secondary substation equipment.
Remove or place the modem board only when the auxiliary supply voltage is turned off
and the telephone line is disconnected. Connect the telephone line after the board is in-
stalled in the cabinet.
As the modem and the equipment in which the modem is placed contain ESD sensitive
components, always take the necessary precautions to avoid electrostatic discharges before
removing or placing any of the printed circuit boards. Disregarding these precautions can
cause damage to internal electronics even in the long run.
2.11 Powering-up
Before applying the auxiliary voltage, check that the modem board is correctly mounted.
Refer to the previous section ‘Mounting’.
The modem board is powered through the equipment it is placed in and does not need a
separate power supply.
As soon as the auxiliary voltage is applied, the modem performs a self-test, after which it is
initialized.

15
3.0 Command overview
3.1 Introduction
AT commands are the means by which the modem is configured. The available commands
enable reading and modifying of the modem parameters. This chapter describes the AT
commands recognized by the 1MRS119000 modem board. The sections of this chapter
describe the command syntax and give a detailed description of the available AT com-
mands and S registers. For a brief description of the commands refer to appendices.
3.2 Command syntax
3.2.1 DTE Commands
The ISO 646 character set (CCITT T.50 International Alphabet 5, American Standard
Code for Information Interchange) is used for issuing commands and responses. Only the
low-order 7 bits of each character are used for commands or parameters; the high-order bit
is ignored. Upper-case characters are equivalent to lower-case characters.
3.2.2 AT command guidelines
Modem operation is controlled by generic AT commands. These AT commands may be
basic AT (i.e., commands preceded by AT, AT&, AT%, AT*, AT\, AT), AT, or AT#), S
register (e.g., S6=n), commands. The command syntax and operation guidelines govern-
ing each of these command categories are described in the subsequent sections.
3.2.3 Basic command syntax
Characters within the command line are parsed as commands with associated parameter
values. The basic commands consist of single ASCII characters, or single characters pre-
ceded by a prefix character, followed by a decimal parameter (e.g., `&D1`). Missing deci-
mal parameters are evaluated as 0.
3.3 AT command
3.3.1 AT command guidelines
The basic AT commands used to control modem operation are defined in this section.
These commands are summarised in Appendix A. All these commands may not be avail-
able in a specific product depending upon supported data rates and modes. The default
values are typical of a fully configured modem supporting all data rates and options. The
actual default value is dependent upon modem firmware as defined by the firmware release
notes.
3.3.2 AT Commands, DTE Adaptation
Under AT operation, the serial interfaced modem performs an autobaud/autoparity/
autolength function on each AT header entered. The autolength/autoparity facility can
detect 7- or 8-bit characters of even, odd, or no parity with one stop bit.

16
3.3.3 AT Command Format
A command line is a string of characters sent from a DTE to the modem (DCE) while the
modem is in a command state. A command line has a prefix, a body, and a terminator.
Each command line (with the exception of the A/ command) must begin with the charac-
ter sequence AT and must be terminated by a carriage return. Commands entered in upper
case or lower case are accepted, but both the A and 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 char-
acters other than CR (ASCII 013) and BS (ASCII 010) in the command string are ignored.
The default terminator is the ASCII <CR> character. Characters that precede the AT pre-
fix are ignored. The command line interpretation begins upon receipt of the carriage re-
turn 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 pre-
ceded by a prefix character (e.g., `&"), followed by a decimal parameter. Missing decimal
parameters are evaluated as 0.
The modem supports the editing of command lines by recognizing a backspace character.
When modem echo is enabled, the modem responds to the 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. A command line may be aborted at any time by entering < cntrl-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 of the commands entered with parameters out of range will be rejected and the
ERROR response will be returned to the DTE.
Commands will be accepted by the modem once the previous command has been fully
executed This 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.
3.3.4 Escape Code Sequence
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 pre-sequence time), a guard time following the
third character (the post-sequence time), and a guard time-out between the first and sec-
ond characters and between the second and third characters (the inter-character time).
These times are controlled by the value recorded in register S12.

17
3.4 AT Commands
The modem will respond to the commands detailed below. Parameters applicable to each
command are listed with the command description. The defaults shown for each configu-
ration command are those used in the Rockwell factory profile.
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 com-
mand) 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 termi-
nated by a carriage return.
AT= x - Write to Selected S register
This command writes the value x to the currently selected S register. An S register can be
selected by using the ATSn command. All of the S registers will return the OK response if
x is a number. Some registers may not be written due to country-specific PTT limitations.
Result Codes:
OK For all arguments.
AT? - Read Selected S register
This command reads and displays the selected S register. An S register can be selected by
using the ATSn command.
Result Codes:
OK For all arguments.
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 ena-
bled. (Most countries do not require Line Current Sense.) The operation is also dependent
upon country-specific requirements.
Bn - CCITT or Bell
When the modem is configured to allow either option, the modem will select Bell or
CCITT 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. The
parameter value, if valid, is written to S27 bit 6. (Also, see ATFn command.)
B0 Selects CCITT operation at 300 or 1200 bps during Call Establishment and a
subsequent connection. (Default.)
B1 Selects BELL operation at 300 or 1200 bps during Call Establishment and a subse-
quent connection.
Result Codes:
OK n = 0 or 1.
ERROR Otherwise.

18
Cn - Carrier Control
This command is included for compatibility only, and has no effect other than returning a
result code. The only valid parameter is 1.
Result Codes:
OK n = 1.
ERROR Otherwise.
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. In W-class models, the action of going off-
hook is affected by the status of the Line Current Sense input, if line current sensing is
enabled, and by the blacklist and delayed list.
NOTE: If the ATD command is issued before the S1 register has cleared, the modem will
respond with the NO CARRIER result code. Accordingly, with some country-specific regula-
tions, the modem will answer DELAYED when you are making repeated call attempts, without
getting any connection and BLACKLIST will be the answer if you are dialling a forbidden
number.
Dial Modifiers. The valid dial string parameters are described below. Punctuation charac-
ters may be used for clarity, with parentheses, hyphen, and spaces being ignored.
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.
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: pulse dial the numbers that follow until a "T" is encoun-
tered. Affects current and subsequent dialling. Some countries prevent changing
of dialling modes after the first digit is dialled.
T Select tone dialling: tone dial the numbers that follow until a "P" is encountered.
Affects current and subsequent dialling. Some countries prevent changing of dial-
ling modes after the first digit is dialled.
R This command will be accepted, but not acted on.
S=n Dial the number stored in the directory (n = 0 to 3 or 0 to 19 depending on the
modem model). (See &Z.)
! Flash: the modem will go on-hook for a time defined by the value of S29. Coun-
try requirements may limit the time imposed.
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.
@ Wait for silence: the modem will wait for at least 5 seconds of silence in the call
progress frequency band before continuing with the next dial string parameter. If
the modem does not detect these 5 seconds of silence before the expiration of the
call abort timer (S7), the modem will terminate the call attempt with a NO AN-
SWER message. If busy detection is enabled, the modem may terminate the call
with the BUSY result code. If answer tone arrives during execution of this param-
eter, the modem handshakes.

19
& Wait for credit card dialling tone before continuing with the dial string. If bong 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 mo-
dem 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 not enter call progress until 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.
( ) Ignored: may be used to format the dial string.
- Ignored: may be used to format the dial string.
<space> Ignored: may be used to format the dial string.
<i> Invalid character: will be ignored.
> If enabled by country-specific parameter, the modem will generate a grounding
pulse on the EARTH relay output.
En - Command Echo
The modem enables or disables the echo of characters to the DTE according to the param-
eter supplied. The parameter value, if valid, is written to S14 bit 1.
E0 Disables command echo. (Default.)
E1 Enables command echo.
Result Codes:
OK n = 0 or 1.
ERROR Otherwise.

20
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, be 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 ig-
nored 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.
F6 Select V.32 bis 4800 or V.32 4800 as the only acceptable line modulation for a subse-
quent connection. Sets N0, sets S37 to 8, and clears S31 bit 1. This command is
equivalent to the command string: ATN0S37=8.
F7 Selects V.32 bis 7200 as the only acceptable line modulation for a subsequent con-
nection. Sets N0, sets S37 to 12, and clears S31 bit 1. This command is equivalent to
the command string: ATN0S37=12.
This setting also allows connection at the Rockwell proprietary 7200 V.32 speed,
e.g., with an RC9696/12-based modem.
F8 Selects V.32 bis 9600 or V.32 9600 as the only acceptable line modulations for a
subsequent connection. Sets N0, sets S37 to 9, and clears S31 bit 1. This command is
equivalent to the command string: ATN0S37=9.
F9 Selects V.32 bis 12000 as the only acceptable line modulation for a subsequent con-
nection. Sets N0, sets S37 to 10, and clears S31 bit 1. This command is equivalent to
the command string: ATN0S37=10.
This setting also allows connection at the Rockwell proprietary 12000 V.32 speed,
e.g., with an RC9696/12-based modem.
F10 Selects V.32 bis 14400 as the only acceptable line modulation for a subsequent con-
nection. Sets N0, sets S37 to 11, and clears S31 bit 1. This command is equivalent to
the command string: ATN0S37=11.