Comtech EF Data CDM-750 - Manual (Page 111)

CDM-750 Advanced High-Speed Trunking Modem Revision 2
Front Panel Operation MN-CDM750
5–33
5.2.2.6 CONFIG: CnC
Appendix D. D OUBLE T ALK C ARRIER ‐ IN ‐C ARRIER OPTION
Carrier-in-Carrier: Mode
Search-Delay ()
Use the W X arrow keys to select Mode or Search‐Delay, and then press ENTER.
5.2.2.6.1 (CONFIG) Carrier-in-Carrier: Mode
CnC operation requires installation of the DoubleTalk Carrier‐in‐Carrier module. In
addition to installing the CnC module, the user needs to purchase one of several
available FAST options to provide capability to a maximum of 155 Mbps.
Appendix A. FAST OPTIONS AND ACTIVATION PROCEDURE
CnC Mode: Off (Off,On)
( v)
Use the STarrow keys to select Off or On, and then press ENTER. With no module installed, CnC
Mode is forced Off and this submenu is inoperable.
5.2.2.6.2 (CONFIG) Carrier-in-Carrier: Search-Delay
CnC Search Delay: (range 0-300ms)
Min: 010 ms Max: 290 ms
( 34v)
To reduce the time taken for the CnC algorithm to converge, you can restrict the range of delay
the search uses. Factory default values for satellite operation are set to a minimum of 230 ms
and a maximum of 290 ms. Once CnC has found the exact delay the value can be further
reduced, but care should be taken to allow sufficient range to accommodate changes in path
delay due to Doppler.
If CnC is being bench‐tested with two units in a back‐to‐back configuration, the
minimum delay should be set to 0 ms, and the maximum to 20 ms. This takes into
account the lack of satellite delay.
To edit the CnC Search Delay: Use the W X arrow keys to select the Min or Max delay digit to edit
using the arrow keys, and then edit the value of each digit by using the ST arrow keys. Press
ENTER when done.