I can explain this if it involves standard network/ethernet hardware. If you are asking about some other type of signal, this information may stil apply but to a lesser degree.
Lets say you have just two devices or nodes on a network. Both nodes send a data transmission, or signal, which has a voltage. When more than one signal is present and detected, it results in a higher voltage which is then sensed as a collision. The transmitted data then becomes intermingled and garbled and is unusable as intended.
When the collision message is transmitted by the detecting hardware, the devices that transmitted the collided data reset a random transmission timer. When the timer runs down, they then attempt to resend their data transmission. If all is successful, both resend data at different times ... until their next collision.
Hope that explains it for you.
