Lucent Technologies AT&T 7400B - Manual (Page 62)

DEFINITY Communications System APPENDIX A: AT COMMAND SET
7400B Data Module
User’s Guide Page A-15
Command: &T
Function: Control diagnostic and test facilities.
Type: immediate
Arguments: The &T command accepts one of eight arguments (see comment 2) as
follows:
0 - (or no option) terminate any test in progress (see comment 3)
1 - initiate local digital loopback test
2 - same as 1
3 - initiate local data loopback test
4 - allow remote digital loopback requests from the remote system
(factory-default selection)
5 - deny remote digital loopback requests from the remote system
6 - initiate remote digital loopback test
7 - initiate remote digital loopback test with self-test
8 - initiate local digital loopback test with self-test
S-Register:
Example:
Comments
Bits 0 and 2—6 of S16 are set according to the argument used with the
&T command.
at&t3 [ Enter ] (see comment 1)
1.
2.
3.
In the example, a local data loopback test is initiated.
All argument values in the range of 0—8 are valid. All of the
options selected by the command arguments described above are
accepted and implemented by the 7400B Data Module, but they
are named differently than in the EIA-232-D standard.
If the local digital loopback or remote digital loopback tests are
in progress, it is necessary to issue the escape sequence to return
to command mode before the
&T0 command can be used to
terminate these tests. The test timer value stored in S18 can also
be set to halt automatically any locally initiated test in progress.
See Also: Chapter 4, “Operation and Configuration;” Appendix B, “S-
Registers.”