> On Oct 4, 2018, at 1:30 PM, Grant Taylor via cctalk <cctalk@classiccmp.org>
> wrote:
>
> On 10/04/2018 11:26 AM, Paul Koning via cctalk wrote:
>> That's sort of accurate. A quick look shows some key differences: V2 adds
>> the "collision presence test" -- verifying the collision detect signal is
>> working. There is also the "jabber timer" -- a watchdog timeout that stops
>> excessively long frames. And V2 introduces the loopback protocol (protocol
>> type 90-00).
>
> That mostly sounds like the frame formats are the same on the wire and that
> the differences are in the protocols that use said frame.
>
>> The collision presence test is somewhat of an interoperability issue: if you
>> attach a V1 transceiver to a V2 NIC, the NIC would complain on every
>> transmit that it didn't get the collision test signal.
>
> That makes me wonder about the "heartbeat" switch that I see on older AUI
> transceivers.
Yes, I think that's the collision test. So in the OFF position you have a V1
compatible transceiver, ON is needed for V2.
paul
