17
AT COMMANDS (continued)
&M232, &Q232 Modem operates in Async mode;
V.25bis Async dialing is enabled.
&M233, &Q233 Modem operates in Sync mode;
V.25 Bisync dialing is enabled.
&M234, &Q234 Modem operates in Sync mode;
V.25bis HDLC dialing is enabled.
&M235, &Q235 Modem operates in Async mode;
AT&T Exclusive dialing is enabled.
&M236, &Q236 Modem operates in Sync mode; the
DTE Dialer Type is disabled.
&Rn
RTS Action
&R0
Standard RS232. RTS action is
controlled by DTE.
&R1
Ignores RTS. Modem ignores RTS
signal and treats it as always ON.
&R2
Simulated Control Carrier. State of RTS
follows state of LSD.
&R3
Control Carrier. DTE’s RTS signal
controls modem’s carrier signal.
&Sn
DSR Control
&S0
Forced On. Forces DSR signal ON.
&S1
Standard RS232. Modem controls DSR
signal.
&S2
Wink When Disc. DSR signal turns Off
for approximately 1 to 2 seconds upon
disconnecting.
&S3
Follows DTR. Modem sends DSR to DTE
when it receives DTR from DTE.
&S4
On Early. DSR is Off when modem is in
idle state. DSR goes ON when modem
enters Data mode.
&S5
Delay to Data. DSR does not turn ON
until the modem enters Data mode.
&S6
Dial Backup toggle.
&Tn
Tests
&T0
Stops any test in progress.
&T1
Starts a Local Analog Loopback test
(V.54, L3).
&T2
Transmits and receives a 511 BERT
pattern.
&T3
Starts a Local Digital Loopback test.
&T4
Accepts request from remote modem for
a Remote Digital Loopback test.
&T5
Denies request from remote modem for a
Remote Digital Loopback test.
&T6
Starts a Remote Digital Loopback test
(V.54, type L2).
&T7
Starts a Remote Digital Loopback test
with a Pattern (V.54, type L2).
&T8
Starts a Local Analog Loopback test
with a Pattern (V.54, type L3).
&T9
Starts a self-test.
AT COMMANDS (continued)
&Vn
View Configuration Options
&V0
Displays Active (Operating) configuration
options.
&V1
Displays Active (Saved) configuration
options.
&V2
Displays Customer 1 configuration
options.
&V3
Displays Customer 2 configuration
options.
&V4
Displays telephone numbers stored in
directory locations 1–10.
&Wn
Write (Save to Memory)
&W0
Saves current configuration options in
Active (Operating) to Active (Saved).
&W1
Saves current configuration options in
Active (Operating) to Customer 1.
&W2
Saves current configuration options in
Active (Operating) to Customer 2.
&Xn
Transmit Clock Source
&X0
Modem provides internal clock source
for synchronous data (Pin 15).
&X1
Modem uses external source (Pin 24) for
clock for synchronous data.
&X2
Modem uses received signal as clock
source for synchronous data.
&Zn=x
Modem stores telephone number x (and
any dial modifiers) in directory location n
(1–10). For example, the command
AT&Z1=555-1234 stores the number
5551234 in directory location 1. To clear
a telephone number from a memory
location, issue &Zn=x without entering a
telephone number.
\An
Maximum Frame Size
\A0
64
\A1
128
\A2
192
\A3
256
\A4
32
\A5
16
\Cn
Error Control Negotiate Buffer
\C0
Data is not buffered during
handshaking sequence.
\C1
Data is buffered up to 4 seconds during
handshaking sequence.
\C2
Data is not buffered during
handshaking sequence; however, the
modem switches to Buffer mode when
it receives an error control fallback
character.