On Nov 23, 22:35, Richard Erlacher wrote:
> It's been a long time since I last put together a coax board uisng a
DP8392
> transceiver, but as I recall the 8392 needed relatively few external
> devices. Its purpose, however, was to drive the coax. I don't believe
> there's any need for it in a TP application.
Well, no, you use a different transceiver IC for that, with a differntial
output, differential input, and some capacitors for pulse-shaping.
> In the classic ethernet/thinnet board design, there was a controller,
e.g.
> AMD 7990, a modulator/demodulator, e.g. AMD 7992, often with the digital
pll
> right in it, and a coax driver like the 8392, but, in AMD's case it was
> another device with more pins and more external parts.. The
> modulator/demodulator drove the AUI outputs, OR, if jumpered
appropriately,
> drove the DP8392. The DP8392 was also the most costly of the three or
four
> popular coax drivers, (AMD, Intel, National, and SEEQ) but it was worth
it
> because of its smaller package size and need for fewer external
components.
I have a few boards (at least one ISA for a PC, and some Acorn cards) which
use the Intel controller and SEEQ. My experience (and that of some others
I've talked to) is that the Intel/SEEQ combination is much less reliable
than the AMD/National ones. It's also much harder to get the ICs for if
you need to repair one.
--
Pete Peter Turnbull
Network Manager
Dept. of Computer Science
University of York
Received on Fri Nov 24 2000 - 03:18:28 GMT