MC55i AT Command Set

MC55i AT Command Set
4.7 AT+IPR
2400
4800
9600
14400
19200
28800
38400
57600
115200
230400
Note
• Generally, AT+IPR should be used as a standalone command as specified in Section 1.4.2, Concatenating
AT Commands. If nevertheless combinations with other commands on the same command line cannot be
avoided, there are several constraints to be considered:
- Avoid combinations with the AT commands listed in Section 1.4.2, Concatenating AT Commands.
- Keep in mind that there shall be a minimum pause between two AT commands as specified in Section 1.5,
Communication between Customer Application and MC55i.
- If AT+IPR=0 is entered, autobauding will be activated after the response to the last command is received.
- If local echo is active (ATE1) and AT+IPR=x is entered with other commands 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 with the new bit rate and thus, not properly transmitted. The following commands will
be correctly sent at the new bit rate.
4.7.1 Autobauding
To take advantage of autobaud mode specific attention must be paid to the following requirements:
• Synchronization between TE and TA:
Ensure that TE and TA are correctly synchronized and the bit rate used by the TE is detected by the TA. To
allow the bit rate to be synchronized simply use an "AT" or "at" string. This is necessary
- after you have activated autobauding
- when you start up the ME while autobauding is enabled. It is recommended to wait 3 to 5 seconds 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 TE-TA synchronization,
when you activate autobauding first and then configure the autoanswer mode (ATS0 ≠ 0).
• Restrictions on autobauding operation:
- The serial interface shall be used with 8 data bits, no parity and 1 stop bit (factory setting), e.g. 2 stop bits
are not supported for autobaud mode.
- The command A/ cannot be used.
- Only the strings "AT" or "at" can be detected (neither "At" nor "aT").
- The second serial interface ASC1 does not support autobauding.
- URCs that may be issued before the ME detects a new bit rate (by receiving the first AT character) will be
sent at the previously detected bit rate or, after ME restart, at 57600 bps.
- It is not recommended to switch to autobauding from a bit rate that cannot be detected by the autobaud
mechanism (e.g. 300 bps). Responses to AT+IPR=0 and any commands on the same line might be corrupted.
• Autobauding and bit rate after restart:
Unless the bit rate is determined, the following constraints apply:
- An incoming CSD call or a network initiated GPRS request cannot be accepted. This must be taken into
MC55i_ATC_V01.201 Page 96 of 482 1/14/09
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