Also see Jabber, an open source program for instant messaging.
In networks, a jabber is any device that is handling electrical signals improperly, usually affecting the rest of the network. In an Ethernet network, devices compete for use of the line, attempting to send a signal and then retrying in the event that someone else tried at the same time. A jabber can look like a device that is always sending, effectively bringing the network to a halt. A jabber is usually the result of a bad network interface card (NIC). Occasionally, it can be caused by outside electrical interference.