Comtech EF Data CRS-400 - Manual (Page 20)

CRS-400 1:8 Redundancy Switch Revision 0
Introduction MN/CRS400.IOM
4
Figure 1-3 depicts the separate Tx and Rx sections of the optional IF switch. Either in the
non-energized state of the relays, or when the switch is not powered, the IF traffic is
routed straight through on the primary units. Traffic enters the Tx section of the switch
from the bottom of the switch and leaves from the top. In the Rx section of the switch,
traffic flows in the opposite direction. There is a loss of 3 dB in the demodulator path
because of the receive splitter.
Figure 1-3 CRS-280 IF Switch Block Diagram (with TMI and RMI Modules)
All of the modulators/demodulators are connected to the CRS-400 via a single, 9-pin,
EIA-485, multi-drop cable and the HSSI cable. The EIA-485 link permits the CRS-400 to
determine and store a modulator/demodulator’s configuration, and to send a chosen
configuration to the redundant modulator/demodulator.
Splitter Splitter Splitter Splitter Splitter Splitter Splitter Splitter Splitter Splitter
DC1 DC2 DC3 DC4 DC5 DC6 DC7 DC8 DC9 DC10
Rx1 Rx2 Rx3 Rx4 Rx5 Rx6 Rx7 Rx8 Rx9 Rx10 RxBU
From Down Converters Not Used
Not Used To Demodulators 6 Through 8 To Redundant
Demodulator
To Demodulators 1 Through 5
Tx2 Tx1 Tx3 Tx4 Tx5 Tx6 Tx7 Tx8 Tx9 Tx10 TxBU
UC1 UC2 UC3 UC4 UC5 UC6 UC7 UC8 UC9 UC10
From Modulators 1 Through 8
From Redundant
Modulator
Test Point To Up Converters Not Used
Not Used
CRS-400.ppt
Controller
Interface
Dr
iv
e
rs
Modulator Switch
Demodulator
Switch