Specifications

Chapter 4 – Serial Interface Control Commands
Multi-Tech Systems, Inc. AT Commands for EDGE Modems (S000371B) 57
Table 4.1 – Availability of AT Commands on Virtual Channels
Command Behavior on Channel 1 Behavior on Channel 2=3
+++ not usable, but see note 2) not usable, but see note 2
AT+CBST as described not usable
AT+CRLP as described not usable
AT+CG... (GPRS commands) as described see note 3.
AT+F... (Fax commands) as described not usable
AT&S as described not usable
ATA as described no Data Calls
ATD as described no Data Calls
ATDI as described not usable
ATL as described not usable
ATM as described not usable
ATO as described not usable
ATS6 See Note 1 as described not usable
ATS7 See Note 1 as described not usable
ATS8 See Note 1 as described not usable
ATS10 See Note 1
ATS18 See Note 1
Notes:
1. GSM engines support the registers S0 - S29. You can change S0,S3,S4,S5,S6,S7,S8,S10 and S18 using the
related ATSn commands (see starting from ATS0). The other registers are read-only and for internal use only!
2. 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 [5], Section “Escape Sequence”.
3. 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 established on two channels at a time.
Table 4.2 – Summary of AT Commands with Different Behavior in Multiplex Mode
Command Description
AT\Q It is recommended to use hardware flow control (AT\Q3). XON/XOFF flow control
(AT\Q1) is not supported in Multiplex mode.
See note regarding AT\Qn settings stored with AT&W if Multiplex mode is active.
AT&V Different default configurations on channels 1, 2 and 3.
AT&W Different user profiles can be stored on each channel.
AT+IPR Before you start Multiplex mode, it is recommended to set the ME to 57600 bps
(minimum should be 4800 bps). For GPRS we suggest to use 115200 bps or 230400 bps.
In Multiplex mode, the write command AT+IPR=<rate> will not change the bit rate currently used,
but the new bit rate will be stored and becomes active, when the module is restarted.
AT+IPR=0 Multiplex mode cannot be activated while autobauding is enabled.
AT+CALA On each channel an individual <text> message can be stored. but only one time setting applies to
all channels. This means an alarm <time> set on one of the channels overwrites the time setting
on all remaining channels. Therefore, the total number of alarm events returned by the read
command AT+CALA? will always be <n>=0, no matter whether individual text messages are
stored.
When the alarm is timed out and executed the ME sends the URC only on the channel where the
most recent alarm setting was made. The alarm time will be reset to “00/01/01,00:00:00” on all
channels.
AT+CMEE Presentation mode can be separately configured for each channel.
AT+CNMA If Multiplex mode is activated the +CNMI parameter will be set to zero on all channels, if one
channel fails to acknowledge an incoming message within the required time.
AT+CNMI Phase 2+ parameters can only be used on one channel. The parameter for <mt> and <ds> 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 channels.
AT+CFUN If the ME is in Multiplexer mode, it is not recommended to activate SLEEP mode with
AT+CFUN=<fun>. The best approach to properly control SLEEP mode in this case is to issue the
PSC messages described in [5], Section “Power saving control (PSC)”.
AT+CPMS Parameter <mem3> will be the same on all instances, but the settings of <mem1> and <mem2>
may vary on each instance.
AT^SSDA If one instance is set to <da>=1 and <mt>=1, then all other instances must be configured for
<mt>=0.