Cabling To The Cdm-700; Modem-To-Switch Control And If Interface Connection - Comtech EF Data CRS-180 Installation And Operation Manual

CRS-180 70/140 MHz IF 1:1 Redundancy Switch
Cables and Connections
4.5

Cabling to the CDM-700

1. For information on configuring the CRS‐180 70/140 MHz IF 1:1 Redundancy Switch
with the CDM‐700 Satellite Modems for 1:1 operation, see:
• Chapter 3. MODEM AND SWITCH CONFIGURATION
• CDM‐700 Satellite Modem Installation and Operation Manual
2. For information on the cables and cable assemblies specified in this section, see:
• Appendix A. CABLE DRAWINGS
4.5.1

Modem-to-Switch Control and IF Interface Connection

Figure 4‐27 shows the control and IF connections for the CDM‐700 to the CRS‐180. All control
and IF components are provided in the KT/12554 CRS‐180 70/140 MHz IF 1:1 Redundancy Kit
(terrestrial data interface components/kits must be ordered separately – see Sect. 4.5.2 for
more information). Note the following:
1. Use of the XF/BNC‐MF‐50‐75 transformers (Item 2) is required on the Rx (J7) and Tx (J8)
connectors, located on the antenna side of the switch, when the user supplies a 75Ω Rx/Tx
connection.
2. Use of the XF/BNC‐MF‐50‐75 transformers (Item 2) on the Rx A and Rx B ports, located on
the modem side of the switch, is dependent on the CDM‐700's factory configuration for 50Ω
or 75Ω Rx operability. If the modems in use are configured as 50Ω Rx units, the
transformers will not be used on the Rx side and the 50Ω cable (Item 4) will be used in place
of the 75Ω cable (Item 3).
3. To provide User access to modem "Fault Summary Relay," Control 'Y' Cable CA/WR13011‐4,
sold separately, is available for use in place of the CA/WR12135‐1 cable.
4. Control Cable CA/WR12135‐1 will mute the Offline modem's Tx IF. If this is not desired, then
an alternate cable, Control Cable CA‐0000187, sold separately, is available for use in place of
the CA/WR12135‐1 cable.
(CEFD P/N MN/CDM700.IOM)
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Revision 8
MN/CRS180.IOM