28 Dec
2003
28 Dec
'03
8:34 p.m.
Have you got a
proper thinwire segment between all of them? The one thing
Thinwire/thickwire = does this equal x-length of good 50 ohm coax with
BNCs on either end? If so - thats covered. What I'm *not* doing is terminating - I didn't figure I'd have to with
each connector on the
servers joined by a single run of coax. I have the BNC Ts - should each
end also need 50 Ohms...? Mongo not Grok LAN voodoo...
YES. You _must_ terminate both ends of the thinwire segment, no matter
how short it is. This is due to the design of the ethernet transceiver,
the transmit part of which is a current source that develops a voltage
across the terminator resistors. If you don't terminate properly, then
the votlage on the network cable goes too high, which is exactly how a
colision is detected...
Fit the T-pieces and 50 Ohm terminetors (a BNC plug with a 50 ohm -- or
51 ohm -- resistor between pin and case) at each end and try again.
that always
caught my customers out was the end connections MUST be t-pieces
with 50 ohm terminators, even on the servers. If you've got a DS90 on its
own it must have a t-piece with 2 terminators on its thinwire port,
2 50 Ohm terms per port? Mongo very confused now... Mongo Least