Bnc Port - Allied Telesis AT-MR420TR Installation Manual

AT-MR420TR and AT-MR820TR Installation Guide
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).

BNC Port

10Base2 requires an RG58U, thin coaxial cable. This cable is a 10
Mbits/sec baseband with 50 Ω impedance. See Figure 10. Connected
with BNC-series connectors, the maximum segment length is 185
meters (606 ft.).
10Base2 (Thin) Ethernet. When configuring thin coax segments, IEEE
802.3 specifications allow 30 or fewer MAUs per cable segment spaced
at no less than 0.5 meter (1.64 ft.). The 10Base2 cable length cannot
exceed 185 meters (606 ft.) per 10Base2 cable segment. The worst case
propagation delay for a 185 meters (606 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 50Ω
termination with a power rating of 0.5 watts or greater. The
AT-MR420TR and AT-MR820TR repeaters provide internal 50Ω
terminator with a slide switch. Earth grounding of the segment shield
is required at only one point on the cable.
Figure 10: BNC-T Connector
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