AT&T DataPort PCX Modem User Manual page 55

AT Commands and S-Registers
Table B-1. AT Command and S-Register List (16 of 21)
AT Command/
S-Register
&M n
B-16
Issue 2
Description
ASYNC/SYNC MODE AND COMPUTER DIALER
TYPE
Applies to external DataPort PCX modem only.
Determines the DTR operating mode. The modem
treats the &M command as a subset of the
&Q command. &M1, &M2, and &M3 are for serial
interface operation (external modem) only.
&M, &M0 Enables direct asynchronous operation.
&M1 Enables synchronous Connect mode with
asynchronous offline Command mode.
&M2 Enables synchronous Connect mode with
asynchronous offline Command mode, and
enables DTR dialing of directory slot 0.
&M3 Enables synchronous Connect mode, and
allows DTR to act as a talk/data switch. A
call is manually initiated when DTR is
inactive. When DTR becomes active,
handshaking proceeds in originate or
answer mode (depending on the modem
state).
July 1995