Re: Ethernet versions

Quinn Nguyen (amdcad!amd!nguyen@ucbvax.Berkeley.EDU)
11 Nov 87 00:46:14 GMT

In article <4800@elroy.Jpl.Nasa.Gov>, david@elroy.Jpl.Nasa.Gov (David Robinson) writes:
> As most people know their are a couple ethernet standards, Version 1,
> Version 2 and IEEE 803.2. When one installs a new ethernet board
> ...
> The question: What is the difference between the versions and what
> effect is their on the physical wire to run two different types
> of transeivers? I have heard people say that it is best to have all
> the same type but no "real" evidence to base that comment on.

Ethernet version 2 and ANSI/IEEE 802.3 (10BASE5) signals are
physically the same.
Version 1 and 2 signals are the same in the coax.
The main differences are on the Drop cable:
- SQE (Signal Quality Error) generation after a packet transmission
required for version 2 and 802.3 but not for version 1.
- Half-step idle signal (differentially 0) with transformer
isolation required for version 2 and 802.3 but not for version 1.
 If a MAU (transceiver) does not generate SQE and only accepts,
generates full-step signals (Ver. 1), it may have problem connecting
to a version 2 DTE or vice versa.
Other issues are device to device line static isolation, ground,
etc. which are not relevant to transceiver connection...
in term of functionality.
  Hope this may help.

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