Comtrol AT Commands - Manual (Page 52)

AT Commands for CX81801/CX06833/CX81300/CX06827 Modems Reference Manual
Conexant 102184B
3-26
&M - Asynchronous/Synchronous Mode Selection
This command determines the DTR operating mode. The modem treats the &M
command as a subset of the &Q command.
Syntax
&M<value>
Defined Values
<value> Decimal number corresponding to the selected option.
0 Selects direct asynchronous operation. The
command sequence &M0\N0 selects normal
buffered mode, but the command sequence
\N0&M0 selects direct mode. This is because the
\N0 command is analogous to the &Q6
command. The value 000b is written to S27 bits
3, 1, and 0, respectively. (See &Q).
1 Selects synchronous connect mode with async
off-line command mode. The value 001b is
written to S27 bits 3, 1, and 0, respectively.
(Serial interface operation only.)
2 Selects synchronous connect mode with async
off-line command mode. Same as &M1 except
that &M2 enables DTR dialing of directory slot
0. The modem will disconnect if DTR is OFF for
more than the period in S25 (in units of
hundredths of a second): the data connection will
be synchronous. The value 010b is written to
S27 bits 3, 1, and 0, respectively. (Serial
interface operation only.)
3 Selects synchronous connect mode. This mode
allows DTR to act as a talk/data switch. The call
is manually initiated while DTR is inactive.
When DTR becomes active, the handshake
proceeds in originate or answer mode according
to S14 bit 7. The value 011b is written to S27
bits 3, 1, and 0, respectively. (Serial interface
operation only.)
Result Codes
OK <value> = 0 to 3
ERROR Otherwise.