1. networking The signal emitted by a Level 2 Ethernet
transceiver at the end of every
packet to show that the
collision-detection circuit is still connected.
2. A periodic synchronisation signal used by software or
3. The "natural" oscillation frequency of a computer's clock
crystal, before frequency division down to the machine's clock
rate.
4. A signal emitted at regular intervals by software to
demonstrate that it is still alive. Sometimes hardware is
designed to reboot the machine if it stops hearing a
(1996-03-12)