Restrictions On Multiplex Mode; Table 4.1: Availability Of At Commands On Virtual Channels - Siemens TC35i User Manual

TC35i AT Command Set
4.11 AT+CMUX
request. Please contact your local distributor to obtain the latest installation software and user's guide.
Parameter Description
(num)
<mode>
Multiplexer transparency mechanism
0
(num)
<subset>
Subparameters defined in GSM07.07 are adjusted for control and logical channels as follows
0
Notes
• The write command is used to enter the multiplex mode. The setup of the logical channels is initiated by the
TE, i.e. the TE acts as initiator. This means that the TE shall ensure that logical channels are established
before any further actions on the channels can be started.
• There is a timeout of five seconds, if the multiplexer protocol is enabled and no multiplexer control channel is
established. The GSM engine returns to AT command mode.
• The parameter maximum frame size (N1) of
All other parameters are not available.
• Multiplexer mode requires character framing to be set to 8 bits, no parity and 1 stop bit. The setting can be
made using (
AT+ICF
4.11.1

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 chapter summarizes the concerned commands. For general rules and
restrictions to be considered in Multiplex mode please refer to [4].
Table 4.1: Availability of AT Commands on Virtual Channels
Command
+++
AT+CBST
AT+CRLP
AT+F... (Fax commands)
AT&S
ATA
ATD
ATDI
ATL
ATM
ATO
TC35i_ATC_V02.07
Confidential / Released
Basic option
UIH frames used only (control channel)
AT+CMUX
=3).
Behavior on channel 1
not usable, but see note
as described
as described
as described
as described
as described
as described
as described
as described
as described
as described
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in GSM07.10 is fixed to 97 and cannot be changed.
Behavior on channel 2+3
2)
not usable, but see note
not usable
not usable
not usable
not usable
no Data Calls
no Data Calls
not usable
not usable
not usable
not usable
s
m
obile
2)
1/30/04