Z02205
ZiLOG
Modem Controller
PS001000-MOD0599 15
M Speaker On/Off Options The country configuration may disable the speaker. If so, this command returns an
ERROR result.
M0 Speaker always off.
M1 Speaker on until carrier detected. This is the default value in North
America.
M2 Speaker always on; stays on after carrier is detected.
M3 Speaker off as digits are dialled, but on during ringback and on until carrier
signal is detected.
O Return to On-Line
Mode
This command returns the modem to the on-line mode. It is frequently used after the
escape character sequence (+++) to resume communication with the remote modem. If
handshaking is started, the modem uses Originate or Answer mode handshaking,
depending upon whether the modem originated or answered the telephone call.
O0 Returns the modem to the On-Line state from the Command state during a
telephone line connection. The modem starts handshaking if no telephone
line connection and the modem was off hook.
O1 Returns the modem to the On-Line state and retrain its data pump during a
telephone line connection. The modem starts handshaking if there was no
telephone line connection is detected but the modem was OFF-HOOK.
&P Pulse Dial Make/Break
Ratios
Sets cadence of pulse dial. The country configuration may disable this command,
forcing particular pulse dialing parameters. In this event, the modem returns an ERROR
result if this command is issued.
&P0 39%/61% make/break ratio and 10 pulses per second when pulse dialing.
This is the default value.
&P1 33%/67% make/break ratio and 10 pulses per second when pulse dialing.
&P2 39%/61% make/break ratio and 20 pulses per second when pulse dialing.
&P3 33%/67% make/break ratio and 20 pulses per second when pulse dialing.
Q Result Code Display
Options
This command allows the user to either display result codes or to not display result
codes.
Q0 Result codes are displayed. This is the default value for North America.
Q1 Result codes are not displayed.
&Q Communications Mode
Options
The &Q command selects the terminal communication mode.
&Q0 Asynchronous. The modem handshakes as the originator if S-register S0
is 0, and as the answerer if S0 is 1. This is the default value for North
America.
&Q1 Synchronous. Hangs up if DTR goes from on to off after the time in S-
register S25 after the CONNECT result code has been sent to the terminal.
Sn Set the current S-register
to n
This command sets the current S-register to the value n selected by the user. For
example, ATS7 will set the current S-register to S7. Default value is 0. Sn addresses a
particular S-register number so future commands like? and = will read of write the S-
register. Modem reset and the &F command select S0 as the default S-register.
? Read an S-Register This command displays the value of the last S-register named in the Sn command.
=x Write an S-register This command writes the value x to the last S-register named in the Sn command. The
range of valid values for x depends upon which S-register is being written. 0 is assumed
if no value is given for x.
T Tone dialing Selects the tone method of dialing.
V Result Code Format This command changes the result code display format
V0 All result codes are displayed as numbers.
V1 All result codes are displayed as words (verbose form). This is the default
value for North America.
Table 2. AT Command Set (Continued)
Command Function and Description
