Comtech EF Data CRS-500, Инструкция по установке и эксплуатации

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CRS-500 1:N Redundancy System
Revision 4
Introduction 1–12 MN-CRS-500
1.3.3 CRS-280/280L IF Switch Unit (ISU)
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Chapter 3. INSTALLATION
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Chapter 5. CABLES AND CONNECTIONS
The CRS-280/280L ISU is intended for use with modems in 1:N redundancy when the Traffic
modems within the redundancy group connect to more than one converter or with different
polarizations or different satellites.
See Table 1-3. Each ISU is available as a separate unit for a variety of IF Band configurations.
Table 1-3. CRS-500 1:N Redundancy System ISU Options
ISU Type Model No. CEFD P/N Frequency, Impedance Connector
70/140 MHz CRS-280
CRS-280
(Configure to Order)
70/140 MHz, 50Ω
Type ‘N’ female
70/140 MHz, 75Ω
L-Band CRS-280L
CRS-280L
Configure to Order)
L-Band, 500 Ω Type ‘N’ female
Each ISU is designed for mounting into the rear or top of a 19-inch rack. It is provided with rack
handles at the front for easy removal from and placement into a rack.
When the entire group of modems is connected to the same transponder, you may bypass using
the CRS-280/280L ISU and, in its place, passively combine or split the modulator outputs and
demodulator inputs. In these applications, the CRS-500 mutes the offline modem’s Tx carrier and
enables the online modem’s Tx carrier.
Note the following:
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Depending on the modem type, the Redundant Modem has multi-band Rx/Tx capability.
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Regardless of bandwidth, when a Traffic Modem fails, the Redundant Modem will be
connected to the appropriate IF signal through the appropriate ISU.
For example, if a Traffic Modem configured for L-Band fails, the Redundant Modem automatically
routes the failed Traffic Modem’s signal to the CRS-280 ISU. The ISU then routes the signal to
the appropriately configured Traffic Modem in the 1:N redundancy setup.