CentreCOM
AT-3675 SNMP-Manageable Learning Bridge
23
10BASE-FL/FOIRL Ethernet
The IEEE 802.3 10BASE-FL standard supports up to 2,000 meters (6,560 ft.)
of multimode duplex fiber optic cable in a point-to-point link which directly
attaches two devices. FL is compatible with FOIRL, but FOIRL supports
connections of 1,000 meters (3,280 ft.). Duplex refers to support for fiber optic
cable pairs, enabling a two-cable fiber optic connection with transmit mode
dedicated to one cable and receive mode on the other. The wide dynamic
range of a fiber optic interface allows for an easy installation. When
connecting fiber optic cable, the receiving pin (RD) is connected to the
transmitting pin (TD) and vice versa.
10BASE2 (Thin) Ethernet
When configuring 10BASE2 coax segments, IEEE 802.3 specifications allow
29 or fewer MAUs per cable segment spaced at no less than 0.5 meter (1.64
ft.). The 10BASE2 cable length can not exceed 185 meters (607 ft.) per
10BASE2 cable segment. The worst case propagation delay for a 185 meters
(607 ft.) thin Ethernet segment is 950.9 ns. The propagation delay for
10BASE2 Ethernet cable is 5.14 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.
10BASE5 (Thick) Ethernet
When configuring 10BASE5 coax segments, IEEE 802.3 specifications allow
100 MAU attachments or less, spaced at multiples of 2.5 meters (8.2 ft.)
measured accurately from the cable end (50
Ω
terminator included). The
10BASE5 cable segment can not exceed 500 meters (1,640 ft.) in length.
Worst case “end-to-end” propagation delay of a 10BASE5 coax segment is
Figure 17: Hub-to-Hub or
MAU-to-MAU Wiring
Not Used
RD-
Not Used
Not Used
RD+
TD-
TD+
Not Used
Not Used
RD-
Not Used
Not Used
RD+
TD-
TD+
Not Used
RJ 45 Pin
RJ 45 Pin
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
Pair twisted as per level 3, 4 or 5 cable
1
1
1
