Interface Design Principles - Huawei MU509 At Command Interface Specification

HUAWEI MU509 HSDPA LGA Module
AT Command Interface Specification
Figure 1-1 Block diagram of interaction between TE and MS

1.2 Interface Design Principles

1.
2.
3.
4.
5.
6.
7.
Issue 04 (2013-01-28)
TE
USER &APPLICATIONS
Each interface should be functionally convergent.
Since the AT command is a packet transmitted via communication port, the
packet size is limited. For the transmission of AT command, in addition to the two
characters "AT", a maximum of 1600 characters can be received (including the
empty characters at the end). For the "response" message or URC reported by
the board, the maximum length is limited to 1600 characters.
Each command line can include only one AT command. For the URC instruction
or response reported from MS to TE, only one AT command is allowed in a
command line.
In order to make the commands and response formats more readable and
standard, except the original interfaces of Qualcomm, in all newly added
interfaces, e.g. no space can be contained in the commands such as AT^XXX:
<arg0>, <arg1>, or behind ^, colon or comma. No redundant space is allowed at
the head or end.
After delivering each AT command, the TE cannot deliver the second AT
command until the MS has made response to this AT command. Otherwise, the
second AT command will not be executed.
For the AT command to which the response is given only after a long time, in
order to prevent interference on other events, it is recommended to report the
final execution result asynchronously. If the MS responds to the TE only after a
long time of waiting, e.g. the "AT+COPS=?" command receives a response only
after a long time after the command is delivered, the MS may have received the
reported instruction of +CREG: XXX on this occasion. Namely, the reporting of
+CREG: XXX may interrupt other responses, and other URCs will not interrupt
the response of command, and the interrupted part of the response will continue
being reported.
Unless otherwise specified, all default codes between TE and MS take on this
format: GSM 7 bit Default Alphabet. See also Section 6 in protocol 23.038. The
character @ is transmitted on the interface still according to 0x00 of 7bit coding.
The board software and API should be able to process this character. The board
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
AT cmds
Result codes
Information text
Network messages
Scope
MT
NETWORK
23