TC63i AT Command Set

TC63i AT Command Set
1.5 Communication between Customer Application and TC63i
1.5 Communication between Customer Application and TC63i
Leaving hardware flow control unconsidered the Customer Application (TE) is coupled with the TC63i (ME) via
a receive and a transmit line.
Since both lines are driven by independent devices collisions may (and will) happen. For example, if the TE
issues an AT command the TC63i starts sending a URC. This will probably cause the TE to misinterpret the URC
being part of the AT command's response. To avoid this conflict the following measures must be taken:
• If an AT command is finished (with "OK" or "ERROR") the TE shall always wait at least 100 ms before sending
the next one. This applies to bit rates of 9600 bps or higher (see AT+IPR). At bit rates below 9600 bps the
delay must be longer: 300 ms at 1200 bps, and 500 ms at 300 bps.
The pause between two AT commands gives the TC63i the opportunity to the transmission of pending URCs
and get necessary service.
Note that some AT commands may require more delay after "OK" or "ERROR" response, refer to the following
command specifications for details.
• The TE shall communicate with the TC63i using activated echo (ATE1), i.e. the TC63i echoes characters
received from the TE.
Hence, when the TE receives the echo of the first character "A" of the AT command just sent by itself it has
control both over the receive and the transmit paths.
Using Backspace at command line:
• As the standard GSM alphabet does not provide a backspace functionality the TC63i is designed to use the
character "08" (hex 0x08) as backspace for command line input. This allows the user to easily erase the last
character when writing an AT command. On the other hand, this solution requires entering the escape
sequence \08 for writing the "ò" character in GSM character string parameters.
Software flow control:
• Regardless of the selected alphabet, keep in mind that, when software flow control is activated, decimal 17
and 19 are interpreted as XON/XOFF control characters.
TC63i_ATC_V01.100 Page 19 of 547 11/10/08
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