4 Oct
2018
4 Oct
'18
10:39 a.m.
On Oct 4, 2018, at 1:30 PM, Grant Taylor via cctalk
<cctalk at classiccmp.org> wrote:
On 10/04/2018 11:26 AM, Paul Koning via cctalk wrote:
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
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.