Sierra Wireless MC8775 Reference Manual page 56

MC87xx Extended AT Command Reference
Table 4-2: Diagnostic command details (Continued)
Command
!CMUXLPBK = <bitmask>
!CMUXLPBK?
Supporting Mini Cards:
•
All
56
Configure ports into loopback mode / query loopback
state
This command is used to select a multiplexed port and to loop data traffic
between the host and the modem over that port.
The modem is effectively in loopback mode only after the modem is put
into mux mode (using the command AT+CMUX). You can, however, issue
AT!CMUXLPBK before or after AT+CMUX. Loopback mode is NOT
supported on the mux control channel since flow control and other modem
signaling is passed on this port.
Usage:
•
AT!CMUXLPBK=<bitmask> selects a specified multiplexed port.
•
AT!CMUXLPBK? returns the current setting.
You can have two ports in loopback mode.
When the modem is in loopback mode, the loopback occurs just as data is
passed to the application layer of the modem. Therefore, the processing
time of this command includes the processing overhead of packet
disassembly and reassembly as the packets are received and echoed
back to the host.
To exit loopback mode when the AT data port is in loopback, you must
reset the modem. To exit loopback mode on other ports, enter the
command with the appropriate bit in the bitmask set to 0. To disable
loopback mode on all ports, enter AT!CMUXLPBK=0x00.
Parameters:
<bitmask> (16-bit hexadecimal bitmask that identifies the port)
•
Bit 0—AT data port
•
Bit 1—Diag port
•
Bit 2—HIP (CnS) port
•
Bit 3—reserved
•
Bit 4—PDP1 port
•
Bit 5—reserved
•
Bit 6—reserved
•
Bit 7–15—reserved
Examples:
AT!CMUXLPBK=0x01—sets the AT data port into loopback mode
AT!CMUXLPBK=0x10—sets PDP1 into loopback mode
Description
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