Command Reference Guide

3Com Router 5000 Family and Router 6000 Family cngced-detection ● 37
Command Reference
cngced-detection
Purpose Use the cngced-detection command to set the threshold parameters for
CNG/CED signal detection.
Use the undo cngced-detection command to restore the default.
Syntax cngced-detection threshold times
undo cngced-detection
Parameters threshold
Calling tone/Called terminal identification (CNG/CED)
detection threshold with fax. It is an integer in the
range 0 to 30 and its default is 0.
times
Threshold of CNG/CED detections with fax. It is an
integer in the range 0 to 100 and the default is 10.
Example Set the threshold argument to 5 and the times argument to 20 in voice
subscriber-line view for CNG/CED signal detection.
[Router-voice-line0] cngced-detection 5 20
View This command can be used in the following views:
■ Voice Subscriber-Line view
Description CNG is generated when the fax machine at the calling end starts, while CED is
generated when the fax machine at the called end starts.
A voice gateway determines fax state by detecting CNG/CED. The likelihood of
detection failure or error exists however depending on the environment where the
device is deployed. As a solution, you can use this command to tune the CNG/CED
detection sensitivity and reliability.
As the threshold value is increasing, detection reliability increases; if you assign a
value that is too large, however, detection may fail as well. The same applies to the
setting of the
times argument.
The times argument specifies the lower limit of the CNG/CED duration. For
instance, the default of
times is 10; this means the CNG/CED signal must last at
least 300 milliseconds to be regarded valid. As the
times value is incrementing by
one, the minimum CNG/CED signal duration increases by 30 milliseconds.