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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.
Java
Object-oriented programming language developed at Sun Microsystems to solve a number of problems in modern programming practice. The Java language is used extensively on the World Wide Web, particularly for applets.
JDBC
Java Database Connectivity. Java API that enables Java programs to execute SQL statements. This allows Java programs to interact with any SQL-compliant database. Because nearly all relational database management systems (DBMSs) support SQL, and because Java itself runs on most platforms, JDBC makes it possible to write a single database application that can run on different platforms and can interact with different DBMSs. JDBC is similar to ODBC but is designed specifically for Java programs, whereas ODBC is language-independent. JDBC was developed by JavaSoft, a subsidiary of Sun Microsystems. See also ODBC.
jitter
1. The interpacket delay variance; that is, the difference between interpacket arrival and departure. Jitter is an important QoS metric for voice and video applications.
2. 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.
JPEG
Joint Photographics Expert Group. Graphic file format that was adopted as a standard by the ITU-T and the ISO. JPEG most often is used to compress still images using DCT analysis.
JTAPI
Java Telephony Application Programming Interface. A call control model developed by Sun Microsystems.
jumper
Electrical switch consisting of a number of pins and a connector that can be attached to the pins in a variety of ways. Different circuits are created by attaching the connector to different pins.
junction
A junction is a point in the telecommunications network that comprises a switching office or facility cross-connect and/or ADM hardware, a point of connectivity where multiple fiber links come together, and/or a source or destination for a wavelength path.
JUNET
Japan UNIX Network. Nationwide, noncommercial network in Japan, designed to promote communication between Japanese and other researchers.
JvNCnet
John von Neumann Computer Network. A regional network, owned and operated by Global Enterprise Services, Inc., composed of T1 and slower serial links that provide midlevel networking services to sites in the Northeastern United States.

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