Rainbow Electronics GM862-QUAD-PY - Manual (Page 9)

AT Commands Reference Guide
80000ST10025a Rev. 5 - 09/07/08
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved page 9 of 434
3.2 AT Command Syntax
The syntax rules followed by Telit implementation of either Hayes AT commands, GSM commands
and FAX commands are very similar to those of standard basic and extended AT commands. A
special command (#SELINT, see §3.5.2.1.1) has been introduced in order to have an AT interface
very close to the standard one.
There are two types of extended command:
- Parameter type commands. This type of commands may be “set” (to store a value or values
for later use), “read” (to determine the current value or values stored), or “tested” (to determine
ranges of values supported). Each of them has a test command (trailing =?) to give information
about the type of its subparameters; they also have a Read command (trailing ?) to check the
current values of subparameters.
- Action type commands. This type of command may be “executed” or “tested”.
• “executed“ to invoke a particular function of the equipment, which generally involves more
than the simple storage of a value for later use
• “tested” to determine:
(if the command #SELINT=0 or #SELINT=1 has been issued, see §3.5.2.1.1)
if subparameters are associated with the action, the ranges of subparameters values that
are supported; if the command has no subparameters, issuing the correspondent Test
command (trailing =?) raises the result code “ERROR”.
Note: issuing the Read command (trailing ?) causes the command to be executed.
(if the command #SELINT=2 has been issued, see §3.5.2.1.1)
whether or not the equipment implements the Action Command (in this case issuing the
correspondent Test command - trailing =? - returns the OK result code), and, if
subparameters are associated with the action, the ranges of subparameters values that
are supported.
Action commands don’t store the values of any of their possible subparameters.
Moreover:
• (for #SELINT=0 or #SELINT=1 only)
An enhanced test command (trailing =??) has been introduced to maintain backward
compatibility for those commands whose subparameters changed the range of possible
values from version to version.
• (for #SELINT=2 only)
The response to the Test Command (trailing =?) may be changed in the future by Telit to
allow the description of new values/functionalities
• (for #SELINT=2 only)