Lucent Technologies AT&T 7400B - Manual (Page 59)

APPENDIX A: AT COMMAND SET DEFINITY Communications System
7400B Data Module
Page A-12 User’s Guide
Command: &C
Function: Data Carrier Detect (DCD) options.
Type: configuration
Arguments: The &C command accepts one of two arguments as follows:
0 - (or no argument) maintain the DCD circuit on at all times
(factory-default setting)
1 - the DCD circuit operates according to the EIA-232-D standard
S-Register:
Example:
Comments:
Bit 5 of S21 is set according to the argument used with the &C
command.
at&c1 [ Enter ]
In the example, the DCD circuit operates according to the EIA-232-D
standard. This would be an appropriate setting for when the 7400B
Data Module is used at a remote site.
Regardless of which option is currently in effect, the DCD circuit of
the 7400B Data Module is always off during self-test, and turns off for
0.5 second during a disconnect sequence.
See Also: Chapter 4, “Operation and Configuration”; Appendix B, “S-
Registers.”