PN 2110036 Revision 1.0 05/11/99 9-1
9. Host Interface9.1. General Description
The MP215 supports both a SLIP and AT-command interface.
For a complete list of AT commands, the user should reference the Sierra
Wireless Modem User Guide and the AT-Command Extension R2.5.2 reference
guide, which describe the AT and extended AT commands that the MP200 family
of products support.
Note however that the MP215 is not fully backward compatible with other
members of the MP200 family and the differences in AT commands supported and
responses to them are discussed here.
The fact that the MP215 has both CDPD and CS-CDPD modes, coupled with the
nature of running CDPD over a circuit-switched cellular connection, requires that
the response to some commands will differ depending on the mode the modem is
in.
Another major behavioral difference the MP215 has over other MP200-family
products is that the modem will not be on-line connected if the host DTE port is in
the AT-command idle state, i.e. waiting for an AT command. An idle host DTE
port means that that the modem is waiting for another AT command to be entered,
and is not currently executing a command.
All normal operations are performed as needed only when the host DTE port is in
a SLIP session, or during the execution of an AT command. (Being in an active
SLIP session can be thought of as executing the ATD or ATO command, which
runs until the SLIP session is terminated).
This means that if the host DTE port is idle, the MP215 will:
• Not answer an incoming AMPS call
• Not originate an outgoing AMPS call
• Not monitor network status nor switch sub-modes between AMPS and
CDPD.
• Not attempt to register (or re-register on timer expiry)
• Maintain its current registration status (e.g., registered/suspended).