CRS-150 1:1 Redundancy Switch
Revision 2
Introduction
MN/CRS150.IOM
1–2
1.2
Description of Features
Figure 1-2. CRS-150 1:1 Redundancy Switch – Panel Views
Figure 1-2
illustrates the operational features available on the front and rear panels of the
CRS-150 1:1 Redundancy Switch.
The CRS-150 includes, as standard, a universal data interface, which eliminates the need to
exchange interface cards for different applications. Supported interfaces include:
•
EIA-422 (EIA530) DCE
•
V.35 DCE (at rates up to 10 Mbps)
•
Synchronous EIA-232 DCE (at rates up to 300 kbps)
•
LVDS (at rates up to 20 Mbps)
•
Balanced and Unbalanced G.703 at rates up to E2 (8.448 Mbps)
Because CDM-600 operational details are not covered in this manual, the user should refer to the
Comtech EF Data CDM-600/600L Satellite Modem Installation and Operation Manual
as needed to
become familiar with all aspects of the modem before attempting redundant operations.
For Drop and Insert (D&I) applications, the second G.703 port (T1 or E1) found on the rear panel
of the CDM-600 is also provided. The operator does not have to configure the interface type –
control signals from the modems automatically perform the selection.
Clock and data signals in the transmit direction are buffered and fed to both modems in the pair
simultaneously. The Receive IF signal is split and fed to both modems. This means that both
modems see identical Tx and Rx traffic signals all the time, which permits the CRS-150 to
continually compare the fault status of both modems. If the CRS-150 sees an identical fault on
both modems at the same time, it will infer that the fault condition exists in the external system,
and eliminate an unnecessary switchover.
Only one modem in the pair (the online unit) is permitted to transmit its IF carrier signal at any one
instance. For total security, the offline modem mutes its Tx carrier, and the CRS-150 provides
further isolation by using an RF relay within the unit. Unlike some other 1:1 redundancy systems,
which use a passive power combiner for this function (losing approximately 3.5 dB in output power
level), the CRS-150 does not introduce any significant attenuation of output signal level.
Summary of Contents for CRS-150
Page 14: ...CRS 150 1 1 Redundancy Switch Revision 2 Preface MN CRS150 IOM xiv Notes...
Page 22: ...CRS 150 1 1 Redundancy Switch Revision 2 Introduction MN CRS150 IOM 1 8 Notes...
Page 42: ...CRS 150 1 1 Redundancy Switch Revision 2 Connector Pinouts MN CRS150 IOM 3 18 Notes...
Page 74: ...CRS 150 1 1 Redundancy Switch Revision 2 Cable Drawings MN CRS150 IOM A 12 Notes...
Page 76: ...2114 WEST 7TH STREET TEMPE ARIZONA 85281 USA 480 333 2200 PHONE 480 333 2161 FAX...
