0049-2702-XXX Alliance Series Modems – USER MANUAL
08/05/2010
Rev. A
Page 100 of 197
Method 2: Switching the Modem’s DTE Connector Function
As an alternative to using an additional cable to the diagnostic port (as described above), the
Hayes mode command
–N1 (AT –N1)
can be issued
to change the function of the modem’s DTE
connector. This command switches to the modem’s DB-25 connector from its normal function
as DTE connector to instead function as the diagnostic port. (It also disables the physical
diagnostic port, until the normal DTE connector function is restored.)
After issuing the
–N1
command, you can send control commands to the ALX, but you will not
be able to transfer data. To return the DTE connector to its normal function, issue the control
command
JMP
.
If you have used the
–P
command (explained below) to change the diagnostic port data rate, the
rate will revert to 9600 bps when you issue the
JMP
command. However, if you add an
X
to the
JMP
command (
JMPX
), the diagnostic port data rate selected via the
–P
command will remain
effective until the modem is powered down or reset.
Method 3: Modem in a Rack Enclosure
For information on connecting the DTE to the rack controller, see the rack controller instruction
manual.
Control Link Data Rate
You can specify the diagnostic port data rate by using the Hayes mode
–P
command (
AT –P
), as
follows:
-P0
9600 bps (default)
-P3
57.6 Kbps
-P1
19.2
Kbps
-P4
115.2
Kbps
-P2
38.4
Kbps
The
–P
command must be issued prior to issuing the
–N1
(switch DTE connector) or
CONNECT (CON)
command (described below), and it should be issued separately (not in the
same command line with
–N1
or
CONNECT/CON
).
Note:
The diagnostic port does not support flow control. Therefore, if the port on the DTE
cannot support the selected data rate without flow control, you may experience data loss. If this
occurs, try a lower data rate.
Control Commands
The diagnostic software built into the ALX supports the control commands listed in Table 3-2.
These commands can only be used when the ALX is configured for diagnostic port control.
