Comtech EF Data CRS-400 - Manual (Page 18)

CRS-400 1:8 Redundancy Switch Revision 0
Introduction MN/CRS400.IOM
2
The CRS-400 is fully modular in construction. All replaceable modules insert into slots in
the rear. This includes the Controller, Power Supply Units (PSU), Traffic Modem
Interface (TMI) and the Redundant Modem Interface (RMI). Power consumption is
below 25 W for a fully populated switch, so no fan cooling is required.
The CRS-400 incorporates the following key reliability features:
Twin, independent, AC power supplies
Maintains normal traffic paths, error free, when AC power is removed
Note: Redundant Modulator/Demodulator traffic returns to normal traffic path if power is lost
Figure 1-1 CRS-400 Block Diagram with Modems and CRS-280 IF Switch
The function of the CRS-400 Redundancy Switch is depicted in Figure 1-1. User data en-
ters and exits the switch at the left hand side of the diagram, while IF leaves and enters
from the right. The data and clock signals to and from a traffic modulator/demodulator
are routed through a TMI, via a set of relays. There are up to 8 TMIs in the switch,
labeled 1 through 8 in the figure. The relays in the TMI are arranged so that the
unpowered state connects the data signals directly through to the traffic
modulator/demodulator. If the power supplies to the system are lost, or if a TMI carrying
traffic is removed, traffic is not interrupted. In normal circumstances, when the redundant
modulator/demodulator is not in service, no data is carried through the CRS-400
backplane – all data is routed through the TMI.
Traffic
Modem
Switches
(TMI)
&
Redundant
Modem
Switch
(RM I)
1
2
3
4
5
6
7
8
Redundant
1
2
3
4
5
6
7
8
Modem 1
Modem 2
Modem 3
Modem 4
Modem 5
Modem 6
Modem 7
Modem 8
CRS-280
IF
Switch
(Optional)
Modulator
Demodulator
Or
Modem Redund
To
User
Equipm ent
To
Up
Converters
From
Down
Converters
CRS-240
Power Supply
CRS-240
Power Supply
CRS-230
Controller
Remote Control
To All M odem s
IF Switch
Control
System Alarms
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
Redundant
CRS-400
Front Panel Keypad,
LCD and LED Display
CRS-400.ppt
Remote
Pass-Thru