jabber 1. Error condition in which a network device continually transmits random, meaningless data onto the network. 2. In IEEE 802.3, a data packet whose length exceeds that prescribed in the standard. JANET Joint Academic Network. X.25 WAN connecting university and research institutions in the United Kingdom. Japan UNIX Network See JUNET. jitter Analog communication line distortion caused by the variation of a signal from its reference timing positions. Jitter can cause data loss, particularly at high speeds. John von Neumann Computer Network See JvNCnet. Joint Academic Network See JANET. jumper 1.)Term used for patchcords found in a wiring closet. 2.)Electrical switch consisting of a number of pins and a connector that can be attached to the pins in a variety of different ways. Different circuits are created by attaching the connector to different pins. JUNET Japan UNIX Network. Nationwide, noncommercial network in Japan, designed to promote communication between Japanese and other researchers. JvNCnet John von Neumann Computer Network. Regional network, owned and operated by Global Enterprise Services, Inc., composed of T1 and slower serial links providing midlevel networking services to sites in the Northeastern United States.