(snip)
Note, though, that is against the rules.
If both sides are ready to send, at some point in the inter packet gap they will make the decision to send. If a signal is detected past that point, the station must send anyway to generate the collision.
This is needed to make collision resolution fair to all. Otherwise, it would be more or less fair depending on the exact point the carrier sense was done.
Well, okay, but the jam signal is the data that it is required to send.
Well, what do you mean by physical collision? A collision on TP ethernet is detected by receiving a signal during transmission. Do you not call it a physical collision as the two are on different wire pairs?
-- glen