TC45 AT Command Set
4.8 AT+CMUX
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obile
TC45_ATC_V02.02
Page 103 of 461
4/16/04
Confidential / Released
4.8.2
Second serial interface ASC1
The second serial interface ASC1 is intended as an auxiliary interface for applications which need multiple par-
allel access to the module (e.g. to query status information during a data call), but cannot use the GSM 07.10
multiplexing protocol. Therefore this interface offers limited functionality only.
• No DTR, DSR, DCD, RING signals. These hardware lines do not exist. As a result, AT commands controlling
the behavior of these lines (
) are not allowed and return ERROR.
• No Autobauding. The hardware is not capable of automatically detecting the baudrate on this interface, so
the AT command which selects autobauding (
=0) is not allowed and returns ERROR.
• No CSDcalls, so all related AT commands cannot be used and return ERROR.
• No fax calls, so all AT+F commands cannot be used and return ERROR.
• No GSM 07.10 Multiplexer. If issued on the second interface
=0 returns ERROR.
• If the pins of group 0 are not configured as ASC1 the second serial interface is not available. To configure the
pins for ASC1 mode use the command
, to configure the pins for GPIO use the command
.
ASC1 is disabled when the multiplexer is enabled on the first serial interface ASC0. Yet, both ASC1 and the mul-
tiplexer channel 2 are using the same parameters, and thus, the same user defined profile (if any). As a result,
a user profile stored on multiplexer channel 2 takes effect on ASC1 after closing the multiplexer and starting up
ASC1. Likewise, a user profile stored on ASC1 will be loaded on multiplexer channel 2.
This may be a problem when ASC1 is not connected, but flow control (for example
1 or
3) is stored to
the user profile on the multiplexer channel 2. In this case, flow control takes effect on ASC1, when the multiplexer
is switched off. If then for example a large amount of URCs is generated, their transmission might be stopped
due to the flow control. To avoid this problem we recommend that you do not activate flow control on multiplexer
channel 2 when you set up a user profile with
If Multiplex mode is activated the +CNMI parameter will be set to zero on all chan-
nels, if one channel fails to acknowledge an incoming message within the required
time.
Phase 2+ parameters can only be used on one channel. The parameter for
and
on the other channels have to be set to zero. If either a SM or a Status
Report is not acknowledged, all +CNMI parameter will be set to zero on all chan-
nels.
If the ME is in Multiplexer mode, it is not recommended to activate SLEEP mode
with
. The best approach to properly control SLEEP mode in this
case is to issue the PSC messages described in
, chapter "Power saving control
(PSC)".
Parameter
will be the same on all instances, but the settings of
and
may vary on each instance.
If one instance is set to
=1 and
=1, then all other instances must be con-
=0.
Command
Description