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The system can use three types of grounding paths:
• Battery return
The battery return grounding path is the return path for all –48VDC loads in
the system. This path is isolated from other system grounds and connects to
the rest of the central office through the –48VDC return connections located
on the breaker panels of each frame.
• Logic Ground
Some system types require connection to a logic ground. The logic ground
path provides a common voltage reference point between all circuit boards of
a system. Each connection terminates to the system ground. The logic ground
path is shown on your system's interconnect drawing. The logic ground path
does not carry current.
NOTE: If the AC-powered T1100 AS unit uses serial RS232 connections,
the grounding in a standard serial cable will provide the logic ground
necessary for the data transmission.
NOTE: AC-powered T1100 AS units should not be used for RS485, DS0,
V.35, or other network connections unless specified by Tekelec.
• Frame/chassis ground
The frame/chassis ground path provides a low impedance connection for all
metal parts of the entire system, including the frame, doors, shelves, and end
panels. Each frame/chassis connection within the system lineup terminates to
the frame and connects to the main ground by way of Htaps, #6 American
Wire Gauge (AWG) to 1/0 cable.
NOTE: The frame/chassis ground path does not carry current.
For products installed in a frame, the doors installed are grounded to the
frame through a two-hole lug ground wire and through a screw-down latch.
Figure 2-4 shows a cutaway view example of an open frame door showing the
door ground strap.
2-10
Safety and Pre-Installation Requirements
Preliminary
910-2969-001 Revision H, February 2007
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