Allied Telesis AT-200 Series CentreCOM - Handbuch (Seite 10)

AT-200 Single Port Transceiver
3
Data cabling considerations. When configuring 10BASE5 coax segments,
IEEE 802.3 specifications provide the following rules to follow:
❑ MAU attachments limited to 100 per segment
❑ MAU attachments spaced at multiples of 2.5 meters (8.2 ft.) measured
accurately from the cable end (50
Ω
terminator included)
❑ Segment length cannot exceed 500 meters (1,640 ft.)
❑ Worst case “end-to-end” propagation delay for the segment is 2165 ns

Propagation delay of 10BASE5 Ethernet coax is calculated at 4.33 ns/
meter
❑ Both ends of the segment must be terminated with a 50
Ω
termination with a
power rating of 0.5 watts or greater
❑ Earth grounding of the segment shield must take place at only one point on
the cable
Tapping the cable and assembling the transceiver. In addition to the tap
kit supplied with the AT-206, you also need the following tools supplied as
accessory AT-1220-K:
❑ Hex wrench
❑ Combination hex nut driver and coring drill
The clamp assembly has a frame that slides onto the tap body, a pressure block that
holds the cable in place and a button head socket screw. The tap body features a
cable channel that retains the cable and an internal guide slot to accept the
transceiver’s PCB.
The braid terminators are designed to pierce the cable jacket and provide a secure
ground. The probe assembly features a spring-loaded contact (stinger) and threads
into the tap body, ensuring permanent contact with the center conductor.
To install the tap body, cable and clamp assembly
1. Before attaching the tap to the transceiver, make sure the transceiver’s
SQE/Heartbeat switch is in the correct position. Refer to the “Heartbeat
configuration” on page 1.
2. Insert the two braid terminators into the tap body. Refer to the exploded
view of the tap in Figure 2.
3. Determine a tapping location on the cable. These may be found on the cable
at 2.5 meter (8.2 ft.) intervals (usually denoted by black marks).
613-10423-00Book Page 3 Monday, March 4, 1996 2:29 PM