Product specifications

CRS-170A L-Band 1:1 Redundancy Switch Revision 3
Introduction MN/CRS170A.IOM
The receive side of the switch uses both power dividers and relays to provide the redundant modem
interface for three signals multiplexed onto the LNB coaxial cable:
• 950-1950 MHz L-band RX RF from LNB
• 10 MHz frequency reference to LNB
• DC power supply to LNB
The CRS-170A monitors the faults of both modems and determines which modem should be
online. The data switch is built into each terrestrial data interface inside both modems (excluding
CDM-600L [CLM-9600L] and SLM-300L3).
The CRS-170A is designed to support 1:1 redundancy for Comtech EF Data CDM-625, CDM-570L,
CDM-600L (CLM-9600L), CDM-700, CDM-710, and SDM-300L3 modems. Table 1-1 summarizes
the applications including requirements for supporting data switching hardware and software.
Table 1-1. CRS-170A Application Summary
Modem
1:1 L-Band Switch
(see Note 2)
1:1 Data Switch
(see Note 1)
Other Information
(see Note 3)
CDM-625 CRS-170A Built into the CDM-625 Firmware 1.1.1 or higher
CDM-570L CRS-170A Built into the CDM-570L Firmware 1.3.1 or higher
CDM-700 CRS-170A Built into the CDM-700
Firmware 1.1.6 or higher
Chassis Rev. A or higher
CDM-710 CRS-170A Built into the CDM-710
Firmware 2.4.1 or higher
Chassis Rev. A or higher
CDM-600L
(CLM-9600L)
CRS-170A CRS-150
Firmware 1.1.4 or higher.
Hardware Rev. 3 or higher
SDM-300L3 CRS-170A SMS-301 Special version of SMS-301
Notes:
1. For detailed information about the CRS-150 and SMS-301 switches, refer to their
respective Installation and Operation Manuals.
2. Read the Overview in this section for detailed information.
3. Order modems with Type ‘N’ connectors.
IMPORTANT
The off-line modem holds its Rx terrestrial data in tri-state as
commanded by the CRS-170A Switch. Because of this, it is very
important to power down the off-line modem before disconnecting
the modem from the Switch.
The CDM-600L (CLM-9600L) and SDM-300L3 modems do not have built-in switching
capability for the terrestrial data side of the link. For the CDM-600L (CLM-9600L), 1:1
redundancy requires both a CRS-150 switch to act as controller and terrestrial data switch and a
CRS-170A to perform the L-Band switching. The CRS-170A is required because the CRS-150
RF switching is limited to the 70/140 MHz band, and will not handle the high current BUC power
supply multiplexed onto the transmit coaxial cable. Similarly, the SDM-300L3 requires an SMS-
301 switch together with the CRS-170A.
1–2