Tekelec T1000 Hardware Manual page 29

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: Logic ground is not required in an AC environment when the
T1000 AS unit uses only Ethernet connections. Ethernet connections are
the only network connections intended for use with the AC powered
T1000 AS unit. If the AC-powered T1000 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 T1000 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 HtAS,
#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.
910-0095-001 Revision J November 2007
Pre-Installation Site Requirements
2-9