BGS2T AT Command Set
4.8 AT+CMUX
BGS2T_ATC_V01.301
Page 105 of 554
1/31/12
c
Parameter Description
Enable Multiplex mode.
0
Basic option
4.8.1
Restrictions on Multiplex mode
In Multiplex mode, CSD and fax calls can only be set up on logical channel 1. Due to this restriction, AT com-
mands have a different behavior on channels 2+3 compared to channel 1. Several commands are not available,
others return different responses. This section summarizes the concerned commands. For general rules and
restrictions to be considered in Multiplex mode please refer to
Table 4.1:
Availability of AT Commands on Virtual Channels
1) The applicability of the
escape sequence depends on the customer's external application based on the Mulitplexer
Protocol. Recommendations for implementing an appropriate modem status command (MSC) are provided in
, Section "Escape Sequence".
2) PDP contexts can be defined on any channel, but are visible and usable only on the channel on which they are defined
(thus it is not possible to define a context on channel 2 and activate it on channel 3). GPRS connections can be estab-
lished on two channels at a time.
Table 4.2:
Summary of AT commands with Different Behavior in Multiplex mode
<mode>
(num)
Command
Behavior on channel 1
Behavior on channel 2+3
not usable, but see note
1)
not usable, but see note
1)
as described
not usable
as described
not usable
AT+CG... (GPRS commands)
as described
see note
2)
AT+F... (Fax commands)
as described
not usable
as described
no CSD/Fax calls
as described
no CSD/Fax calls
as described
not usable
as described
not usable
as described
not usable
as described
not usable
Command
Description
It is recommended to use hardware flow control (
3). XON/XOFF flow control
(
1) is not supported in Multiplex mode.
See note regarding
n settings stored with
if Multiplex mode is active.
Different default configurations on channels 1, 2 and 3.
Different user profiles can be stored on each channel.
Before starting Multiplex mode, ensure that the bit rate set with
is not lower
than 57600 bps. For using data services in Multiplex mode it is recommended to
set at least 115200 bps.
In Multiplex mode, the write command
=
currently used, but the new bit rate will be stored and becomes active, when the
module is restarted.
Multiplex mode cannot be activated while Autobaud mode is enabled.
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