Expansion Slots; Reference Distribution Module - Comtech EF Data Radyne RCS20 Installation And Operation Manual

RCS20 M:N Redundancy Switch
Electrical Interfaces
5.2.3

Expansion Slots

There are six expansion slots (numbered 0 through 5). The following cards may be inserted into
the slots, as shown in Figure 5-2:
•
Reference Distribution Module (shown installed in Slot 0)
•
CPU Terrestrial I/O Card (shown installed in Slot 1)
•
Bank Control I/O Card (shown installed in Slot 2)
The cards that are currently occupying the expansion slots may be viewed from the front menu
screen by accessing the EXPANSION SLOT MONITOR Screen (see Chapter 4).
The RCU20 MUST be powered down when installing / removing the bank
control I/O OR when cabling up to the IFS20 or DDS20 with the CA3429
cables. Failure to do so can result in damage to the bank control I/O and
cause loss of redundancy in the system.
5.2.3.1

Reference Distribution Module

The Reference Distribution Module RDM (Figure 5-3) is an optional RCU20 expansion card that
is used to buffer and distribute earth station frequency reference(s) to the external reference input
of modems that are connected to an RCS20. The RDM automatically switches between EXT A,
EXT B or Internal References based upon onboard Clock Activity Detect circuits.
Each of the ports on the RDM is a Female BNC Connector. Port function is as follows:
Ref Des
J1
J2
J3
J4
J5
J6
The Reference Distribution Module must be configured with two jumpers to select the
termination impedance. The jumpers, J1 and J2, are shown in Figure 5-4.
Figure 5-3 Reference Distribution Module
Signal Name
EXT A IN
EXT B IN
OUT 1
OUT 2
OUT 3
OUT 4
5–3
Description
Primary Internal Reference Input
Secondary Internal Reference Input
Reference Output 1
Reference Output 2
Reference Output 3
Reference Output 4
Rev. 14
MN-RCS20