Chapter 2 – AT Commands
Multi-Tech Systems, Inc. AT Commands Reference Guide (S000273G) 9
Command: &En Modem-Initiated Flow Control
Note: For use with MT5600BA and MT5600BR only.
Values: n = 3, 4, or 5
Default: 4
Description: &E3 Flow control disabled.
&E4 CTS/RTS hardware flow control.
&E5 XON/ XOFF soft ware flow control.
Note: See also the L5 and &K commands.
Command: &En V.42bis Data Compression
Note: For use with MT5600BA and MT5600BR only.
Values: n = 14 or 15
Default: 15
Description: &E14 V.42bis data compression disabled.
&E15 V.42bis data compression enabled.
Note: This command controls only V.42bis data compression, whereas the %C command
controls both V.42bis and MNP-5 data compression. The command in effect is the
one last entered. See also the L5 command.
Command: &Fn Load Factory Settings
Values: n = 0 or 1
Default: None
Description: &F0 Loads factory configuration 0.
&F1 Loads factory configuration 1.
Note: See also the Z, L5, and &V commands.
Command: &Gn V.22bis Guard Tone Control
Values: n = 0, 1, or2
Default: Varies by country
Description: &G0 Disables guard tone.
&G1 Sets guard tone to 550 Hz.
&G2 Sets guard tone to 1800 Hz.
Note: The &G command is not used in North America, and may not be permitted in some
countries.
Command: &Kn Flow Control Selection
Values: n = 0, 3, 4, 5, or6
Defaults: 3 (data modem mode)
6 (fax modem and voice modes)
Description: &K0 Disables flow control.
&K3 Enables CTS/RTS hardware flow control.
&K4 Enables XON/XOFF software flow control.
&K5 Enables transparent XON/XOFF flow control.
&K6 Enables both CTS/RTS and XON/XOFF flow control.
Note: See also the &E command
Command: &Mn Communications Mode
Values: n = 0–3
Default: 0
Description: This command determines the DTR operating mode. The modem treats the &M command
as a subset of the &Q command.
&M0 Selects direct asynchronous operation. Command sequence &M0\N0 selects
normal buffered mode, but command sequence \N0&M0 selects direct mode. This
is because the \N0 command is analogous to the &Q6 command.
&M1 Selects synchronous connect mode with asynchronous offline command mode.
&M2 Note: For use with the MT5656ZDX and MT5656ZDX-V only. Selects synchronous
connect mode with asynchronous offline command mode.
Same as &M1 except that &M2 enables DTR dialing of directory slot 0. The modem
disconnects if DTR is low for more than the period stored in S25.
&M3 Selects synchronous connect mode. This mode allows DTR to act as a talk/data
switch. A call is manually initiated while DTR is inactive; when it becomes active,
the handshake proceeds in originate or answer mode according to S14 bit 7.