Specifications

TC35i AT Command Set
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TC35i_ATC_V01.05 Page 54 of 278 04.08.2003
Generally, AT+IPR=x should be used as a standalone command. If nevertheless
combinations with other commands on the same line cannot be avoided, there are
several constraints to be considered:
· Avoid combinations with the AT commands listed in Chapter 1.4.2.
· Take into account that a delay of 100 ms is required between a response to the
last command (e.g. OK) and the next command on the same line.
· When you enter AT+IPR=0, autobauding will be activated after the response to
the last command is received.
· When local echo is active (ATE1) and you enter AT+IPR=x with other com-
mands you may encounter the following problem: If switching to the new bit
rate takes effect while a response is being transmitted, the last bytes may be
sent at the new bit rate and thus, not properly transmitted. The following com-
mands will be correctly sent at the new bit rate.
2.47.1 Autobauding
Synchronization between DTE and DCE
Ensure that DTE and DCE are correctly synchronized and the bit rate used by the DTE is detected by
the DCE (= ME). To allow the bit rate to be synchronized simply issue an "AT" or "at" string. This is
necessary
· after you have activated autobauding
· when you start up the module while autobauding is enabled. It is recommended to wait 3 to 5 sec-
onds before sending the first AT character. Otherwise undefined characters might be returned.
If you want to use autobauding and autoanswer at the same time, you can easily enable the DTE-DCE
synchronization, when you activate autobauding first and then configure the autoanswer mode
(ATS0¹0).
Restrictions on autobauding operation
· The serial interface has to be operated at 8 data bits, no parity and 1 stop bit (factory setting).
· The A/ command (and a/) cannot be used.
· Only the strings “AT“ or “at“ can be detected (neither “aT“ nor “At“).
· Unsolicited Result Codes that may be issued before the ME detects the new bit rate (by receiving
the first AT command string) will be sent at the previously detected bit rate.
· The Unsolicited Result Codes "^SYSSTART" and "^SYSSTART ALARM MODE" and “SYSSTART
CHARG-ONLY MODE” are not indicated when you start up the ME while autobauding is enabled.
· It is not recommended to switch to autobauding from a bit rate that cannot be detected by the auto-
baud mechnism (e.g. 300 baud). Responses to +IPR=0 and any commands on the same line might
be corrupted.
· When entering several AT commands on the same line, consider the requirements described in the
Notes of Chapter 2.47.
· See also Chapter 2.46.
Autobauding and bit rate after restart
The most recently detected bit rate cannot be stored when the ME is powered down (with AT^SMSO).
Therefore, the ME will use 57600 bps by default, until the first AT character was transmitted and the bit
rate was correctly detected.
For example, URCs generated after restart will be output with 57600 bps. The same applies to
autoanswer calls if SIM PIN1 authentication is done automatically and autoanswer mode ATS0¹0 is
stored to the user profile determined with AT&W (if not stored to the user profile ATS0 is reset to its
default 000 after restart and thus not relevant for autobauding).
Autobauding and multiplex mode
If autobauding is active you cannot switch to multiplex mode (see Chapter 4.28). Vice versa, when you
run the multiplex mode, the write command AT+IPR=<rate> cannot be used.