AT-30xxSL Multiport Repeaters
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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 cannot exceed 500 meters (1,640 ft.). Worst case “end-
to-end” propagation delay of a 10Base5 coax 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 one and only one point on the cable.
AUI Cables
AUI (Drop) cables cannot exceed 50 meters (164 ft.) each. Attachments can be
made only to the cable ends at the 15-pin D-shell connector. AUI cables can
have a maximum 257 ns propagation delay, as used for computing the worst
case propagation delay of a cable system. AUI cable propagation delay is
approximately 5.13 ns/meter.
This cable internally consists of four shielded twisted pair wires with an
overall shield and drain wire; a 15-pin D-shell male connector at one end and
a 15-pin D-shell female connector at the other end. Cable impedance is
nominally 78
Ω
. The AUI cable typically connects a transceiver attached to a
coaxial segment to a DTE (workstation).
10Base2 (Thin) Ethernet
When configuring thin coax segments, IEEE 802.3 specifications allow 29 or
fewer MAUs per cable segment spaced at a minimum of 0.5 meters (1.64 ft.).
The 10Base2 cable length cannot 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 can occur at one and only one point on the cable.
