My first 10BASE5 network segment
ard at p850ug1.demon.co.uk
Fri Aug 26 00:16:14 CDT 2016
> You will need to terminate the coax.
> (terminator)---------------<tap>------. . .
He said he has connected a 47 Ohm resistor at each end of the
coax. That's close enough to the correct 50Ohm terminal to
> Anyway, you need to terminate the line or your going to have so many issues
> you may not even get a packet to make it from one end of the line to the
Correct. You won't. No matter how short the coax is. You will get collisions.
The reason is that the transmitter in a coax MAU is a current source which
effectively develops a voltage across the terminators. The receiver is a
voltage detector. A collision is sensed by the MAU if it sees more voltage
across the coax than it should. This (on a correctly terminated cable) means
that 2 transmitters are putting current into the cable/terminators at the
But if the termination resistors are too high or missing (even if only one
is missing) then a single transmitter's current will develop enough voltage
across the coax to be detected as a collision.
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