52 097-55501-01 Issue 6 – June 2003
1
TimeHub 5500 System Guide
- If the LED is not lit it most likely indicates that the link cable is
not connected. This can also occur if there are no clocks in the
master shelf that are producing timing outputs. For example,
this would happen if both master shelf clocks were still in War-
mup.
- If the LED is red it indicates that the link cable is attached but
there is a problem receiving either clock timing, clock framing,
or communication from the master shelf. If any one of these
three conditions is not met, the LED will be red.
- If the LED is green it indicates that this EC card is receiving
proper timing, framing, and communication from the master
shelf.
1.7.4 Functions Associated with Expansion Shelf Rear
Side
The rear side of the expansion shelf contains the following types of
connections.
1.7.4.1 Connectors for the Expansion Link Cables
There are four 25 pin connectors along the top of the shelf rear, two (in and
out) for link 1 and two (in and out) for link 2. They are clearly labeled as to
their function. This is described in detail in the next section.
1.7.4.2 Connections for Output Connector Modules
These modules define the output signal type (DS1 or CC) for outputs driven
by output driver cards inserted in the shelf front. The expansion shelf can
accept up to 16 connector modules (of either type), each providing 20
outputs of the selected type. Additional detail provided in later section.
1.7.4.3 Terminal Blocks for Connecting Power to the Expansion
Shelf
There are redundant connections A (shelf upper left) and B (shelf upper
right). See Figures 4-2 and 4-3, and Procedure 4-1, in Chapter 4 for
connection detail.
1.7.5 Expansion Link Cables
The interconnection between master and expansion shelves is via the link
cable. There are two identical links, termed "expansion link 1" and
"expansion link 2". Each link provides identical signaling. The purpose for
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