Modem Commands

Command

Function

Attention. Needed before every other command ( except A/ and the escape code). Example: ATDT

Repeat the last command (Don't use ATA/)

Set to answer mode immediately, without waiting for ring.

Set Bell mode ( 1200 bps protocol compatibility - V.22 or Bell 212A)
Use n=0 CCITT V.22 with 2100Hz Answer Back Tone.
Use n=1 Bell 212A with 2225Hz Answer Back Tone.

Carrier state: n=0, OFF n=1, ON

Use the following symbols in a dialing string.

Symbol	What it does
,	Pauses - for 2 seconds normally.
W	Wait for a tone before dialing the remaining digits.
@	Wait for a "quiet answer" before continuing with a string
!	Flash(go on-hook for 1/2 second). Used to get a new dial tone.
;	Return to beginning after dialing. Must be at the end of a dial string
0-9 # * ABCD	Digits and characters that can be used in a dialing string. (Must be tone dialing for ABCD
T	To set up touch tone dialing.
P	To set up pulse dialing
R	Reverse mode. Used to put the modem in answer mode as soon as dialing is finished.
S=n	Stored number. Used to dial a stored number in some systems

	To Disable Call Waiting: Use *70,, before your digits to dial (in most telecos).

get Dial Tone

Echo modem command( On or Off).
n=0, echo OFF ( NO)
n=1, echo ON (YES)

Full or half duplex operation.
n=0, half duplex
n=1 full duplex

Hook relay set to On or Off hook.
n=0 on hook(disconnect or hang up)
n=1 off hook

Request product code and ROM checksum. Return product ID/checksum.
n=0 Returns product ID. The modem sends its own 3-digit product code.
n=1 Performs checksum, and returns it. Requests numeric checksum from firmware ROM.
n=2 Performs checksum, and returns the result code. Request OK or ERROR state from the ROM checksum.
n=3 returns ROM part number and revision level.

Loudness (volume of speaker)
n=0 low
n=1 low
n=2 medium (prefered)
n=3 high

Mode of speaker control.
n=0 speaker always OFF
n=1 speaker ON when phone is off-hook; OFF when Carrier Detected
n=2 speaker always ON
n=3 speaker ON after dialing until Carrier Detected. Speaker is turned off when carrier signal received.

On-line mode set.
n=0 Online. The modem returns to the on-line state
n=1 Online set with equalizer retrained. (2400 bps mode only)

Quiet command for result codes. Set result codes to ON/OFF.
n=0 codes are sent
n=1 codes are NOT sent

Sn?

Reads the contents of status register Sn. Displays the value of S-register n.

Sn=x

S-register command. Used to modify an S register in the modem. It assigns a value x to the status register n. An &F or Z command resets the register to default values.
n=Status register number x=value to set

Sets result code format. Verbose mode for result codes.
n=0 use digits(numeric)
n=1 use words

Xtended result code enabled and dialing mode set.
n=0 basic(300bps).Dialtone and busy signal not recognized (blind dialing). Result codes 0-4 enabled.
n=1 extended(no dialtone or busy signals are detected). Result codes 0-5 and 100 enabled.
n=2 extended(detects dialtone but not busy signals). Result codes 0-6 and 10 enabled.
n=3 extended(no dialtone detect but detects busy signals). Result codes 0-5,7 and 10 enabled.
n=4 extended(detects both dialtones and busy signals)

Long Space Disconnect Option
n=0 disabled
n=1 enabled; disconnects after receiving 1.6 sec break.

Resets registers to default values with configuration profile from non-volatile memory.

&Cn

Data Carrier Detect(DCD) handling enabled.
n=0 DCD always on. Modem keeps DCD (RS-232 pin 8) always on.
n=1 DCD set by modem when remote carrier detected. DCD tracks data carrier detected by modem.

&Dn

Data Terminal Ready(DTR) handling enabled. DTR ON/OFF time specified by S25.
n=0 modem ignores DTR line (RS-232 pin 20)
n=1 modem switches to asynch command mode when DTR goes off.
n=2 does n=1,DTR off does n=1 plus disables auto answer, switches modem off hook, and returns to asynch command state.
n=3 modem initializes when DTR goes off.

Resets S Registers and Commands to factory default setings from ROM config profile, as a powerup would do.

&Gn

Guard tone selected (only for CCITT modes, not used in US.)
n=0 no guard tones
n=1 550 Hz guard tone
n=2 1800 Hz guard tone

&Jn

selects telephone Jack
n=0 RJ-11/RJ-41S/RJ-45S
n=1 RJ-12/RJ-13

&ln

selects line, dialin or leased
n=0 dialin operation
n=1 leased-line

&Mn

Mode selected for asynchronous/synchronous communication
n=0 asynchronous
n=1 synchronous mode 1 -async dialing, then switch to synchronous operation
n=2 synchronous mode 2 -stored number dialing
n=3 synchronous mode 3 -manual dialing

&Pn

selects make/break pulse length for Pulse dialing
n=0 39% make,61% break(US and Canada standard)
n=1 33% make,67% break

&Qn

Communications Mode Option

	Idle State	On Line State
n=0	Normal	Asynchronous
n=1	Normal	Reserved
n=2	Dial when DTR=1 Hangup when DTR=0	Reserved
n=3	Task/data, DTR=0/1	Reserved

&Rn

Request to Send/Clear to Send handling (sync mode only)
n=0, CTS (RS-232 pin 5) tracks RTS (pin4)
n=1, modem ignores RTS and turns CTS on when ready to receive synchronous data

&Sn

Data Set Ready(DSR) handling. DSR ON indicates that the modem is connected to a communication channel and is ready.
n=0 DSR always ON. Modem forces DSR ON whenever modem is turned on
n=1 DSR (RS-232 pin 6) operates according to EIA specs. DSR turned ON at start of hand- shaking, off in test mode, idle state, or when carrier is lost

&Tn

Test mode(not available in 300bps mode)
n=0 terminate any test in progress after last command on a line, and return to command mode. n=1 initiates local analog loopback test
n=3 initiates local digital loopback test
n=4 sets modem to perform remote digital loopback when requested by another modem
n=5 prohibits remote digital loopback
n=6 initiates remote digital loopback with another modem
n=7 initiates remote digital loopback with self-test
n=8 initiates local analog loopback with self-test

Display active configuration profiles for S Register settings, commands, and telephone numbers. Inputs from DTE are ignored while this information is being sent.

&Wn

Write S registers and command config profile, last DTE speed, and parity to non-volatile RAM for poer up or hard reset.
n=0 store active profile in location 0
n=1 store active profile in location 1

&Xn

Select the synchronous transmit clock source (sync mode only)
n=0 Internal clock, modem generates timing and sends through pin 15
n=1 modem's host computer generates timing and sends it to modem on pin 24, which modem routes to pin 15.
n=2 Receive clock, modem derives timing from incoming signal and supplies it to pin 15

&Yn

Select a stored profile to survive a power outage for power up (in addition to &Y)
n=0 Select profile 0 on power up or hard reset
n=1 Select profile 1 on power up or hard reset See, the &Wn command for particular commands and S Registers stored. The selected &Y command survives a power outage.

&Zn

Stores telephone number. n=string of digits compatible with Dn