Comtech EF Data SMS-458B - Manual (Page 35)

SMS-458B Modem Protection Switch Revision 2
Installation MN/SMS458B.IOM
2–9
2.3.5 Downlink Inputs (J7 to J10, J12 to J15)
These are the downlink-input connectors. These connections provide the inputs to the
downlink-switching matrix.
J7, J8, J9, and J10 Inputs to backup modem 1
Note: J12, J13, J14, and J15are not used with this switch.
Up to four downlinks can be connected to the switch. Downlink inputs that are not being
used must be terminated into 75
Ω.
2.3.6 Back-Up Demods (J11, J16)
J11 and J16 Outputs from the downlink switching matrix
J11 Backup demod 1 output. It connects to the backup modem RX IF input.
Note: J16 is not used in this switch
Any of the 4 downlinks can be directed to J11. The default setting is downlink 1. The
input frequency range is 50 to 180 MHz, with input impedance of 75
Ω. Terminate any
back-up demod port into 75
Ω when not being used.
2.3.7 Prime Mod Inputs (J18 to J25)
J18 through J25 Prime modulator IF input connections to the modulator IF switching matrix.
They connect to the prime modem IF outputs.
Note: J22 through J25 are not used with this switch.
The input frequency range is 50 to 180 MHz, with input impedance of 75
Ω.
Prime mod inputs that are not being used must be terminated into 75
Ω.
2.3.8 Back-Up Mod Inputs (J26, J36)
J26 and
J36 Back-up modulator IF input connectors. They connect to the back-up modem IF
outputs.
Note: J36 is not used in this switch.
The input frequency range is 50 to 180 MHz, with input impedance of 75
Ω.