Comtech EF Data CDM-750 - Manual (Page 30)

CDM-750 Advanced High-Speed Trunking Modem Revision 2
Introduction MN-CDM750
1–6
• 1:1 and 1:N redundancy switching available
1.3.1 Physical Description
The CDM‐750 Advanced High‐Speed Trunking Modem is constructed as a 1RU‐high rack‐
mounting chassis. Handles at the front allow easy placement into and removal from a rack. The
unit can be free‐standing if desired.
• Sect. 1.4 CDM‐750 Specifications
• Sect. 2.1 Installing into a Rack Enclosure
• The modem is modular in design and is comprised of two main card assemblies:
o
The main card includes all of the interface circuits (including Dual and Optical GigE, 10
MHz external reference, redundancy, etc.), the DVB‐S2 Encapsulator/Decapsulator or
alternate framing/deframing, and the EIA‐232/422 and Ethernet M&C interfaces.
o The modem card performs all signal processing functions of modulation, demodulation,
and frequency conversion to 70/140 MHz or L‐Band. This card provides ID capability so
that M&C can identify which card is installed.
Additionally:
ƒ Based on “Adaptive Cancellation” technology, the DoubleTalk TM Carrier‐in‐Carrier ®
option (referred to throughout this manual as CnC) allows transmit and receive
carriers of a duplex link to share the same transponder space. This plug‐in daughter
card can either be factory‐installed at the time of ordering, or field‐installed by the
user.
Appendix D. D OUBLE T ALK C ARRIER ‐ IN ‐C ARRIER OPTION
ƒ An optional K4 GZip lossless compression card plugs into an internal expansion slot
on the modem card.