IBUC Operation Manual
Terrasat Communications, Inc.
Rev. A
7-5
Rx 1+1 Interface Module
Refer to Rx 1+1 Interface Module block diagram on page 7-6.
DC Supply
The Rx 1+1 Module is supplied with a voltage from 20 to 60VDC through connector J2
(from the power supply that powers IBUC A) and connector J3 (from the power supply
that powers IBUC B). Power Supply A is routed to a DC/DC that generates the voltage
that supplies LNB A and Power Supply B is routed to a DC/DC that generates the
voltage that supplies LNB B. Both Power Supplies are routed to a DC/DC that
generates the voltage that supplies all internal circuitry.
Monitor and Control
The Rx 1+1 Interface Module is equipped with monitor and control (M&C) capabilities.
There are five ways to remotely access the M&C capabilities of the Interface. First is via
the M&C 19-pin circular connector (J1) utilizing two wire RS485. In order to access the
RS485, a separate cable must be run and connected to J1. A second way to access
M&C is through the same J1 connector using RS-232. In order to access the RS-232, a
separate cable must be run and connected to J1. A third way to access the M&C is
through the same J1 connector using TCP/IP. This method requires a separate
Ethernet cable. The fourth method is through the same J1 connector using an optional
handheld terminal. The fifth way to access the M&C capabilities remotely is through the
L-band output N-connector (J6) utilizing Frequency Shift Keying (FSK). Using this
method requires no additional cable but does require that the FSK be multiplexed onto
the L-band cable. Modem manufacturers do not offer yet built in FSK capabilities
capable of communicating with the Rx 1+1, but the unit is ready for it when that
happens. Later in this chapter you’ll find specific information on command structure and
commands for this module. The Rx 1+1 Interface Module also provides status alarm
output (Form-C relay) for both LNB’s.
L-Band Signal Flow
The L-band inputs to the Rx 1+1 Interface Module are through the input N-connectors
J5 (LNB A) and J4 (LNB B). The online signal is selected through a RF switch (relay)
and routed to J6 (L-band Rx out) through the mux / de-mux circuitry. Samples of both L-
band inputs (LNB A & B) are detected and sent to the M&C card for monitor purposes.
The 10 MHz reference from the modem (J6) is de-multiplexed and split to feed both
LNB’s. The 10MHz level is detected and sent to the M&C card for alarm processing.
The DC supply (+18VDC) generated internally and the 10 MHz reference are
multiplexed to the L-band signal to feed the LNB’s through connector J5 and J4. Before
multiplexing the DC voltages, the current and voltage that are fed to the LNB’s are
detected and the information is sent to the M&C card.
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