In
laptop computing
Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, ...
, the XJACK is a type of extendable connector or antenna for a
type II PC card, designed by the Megahertz subsidiary of
3Com
3Com Corporation was an American digital electronics manufacturer best known for its computer network products. The company was co-founded in 1979 by Robert Metcalfe, Howard Charney and others. Bill Krause joined as President in 1981. Metcalfe e ...
. When not in use, the XJACK retracts into the PC card for storage.
The XJACK was originally used in modem and network cards, to attach a standard
RJ11
A registered jack (RJ) is a standardized telecommunication network interface for connecting voice and data equipment to a service provided by a local exchange carrier or long distance carrier. Registration interfaces were first defined in th ...
or
8P8C plug directly to the PC card. They do not require a separate dongle, which could be lost or misplaced, and do not need to be removed from the laptop when travelling. An alternative approach is to use larger
type III cards with a regular
modular connector
A modular connector is a type of electrical connector for cords and cables of electronic devices and appliances, such as in computer networking, telecommunication equipment, and audio headsets.
Modular connectors were originally developed fo ...
socket, but this approach requires more space.
Wi-Fi
Wi-Fi () is a family of wireless network protocols, based on the IEEE 802.11 family of standards, which are commonly used for local area networking of devices and Internet access, allowing nearby digital devices to exchange data by radio wav ...
PC cards for accessing wireless networks have an external portion containing the antenna for improved reception (as compared with inside the laptop), but this portion of the card may be accidentally damaged while moving the laptop. 3Com manufactured wireless cards with retractable antenna portions, also under the XJACK name.
Other companies have since manufactured wireless cards with retractable antennas.
[{{cite web , url=http://www.akihabaranews.com/en/news-11071-AX420S,+the+PHS+204kbps+CF.html , title=AX420S network card , access-date=2008-08-01]
References
Computer connectors