Callback Modem:-

Also known as dial back modem. A special modem that- does not answer an incoming call, but instead required the caller to enter a code and hand up so that the modem can return the call. As long as the entered code matches a previously authorized number, the modem dials the number.

Callback modems are useful in installations for which communications lines must be available for remote users but data must be protected from intruders.

Campus Network:-

A network that connects local-area networks (LANs) from multiple departments inside a single building or set of buildings. Campus networks are LANs because they do not include wide-area network (WAN) services, even though they may extend for several miles.

Carrier Signal:-

A signal of chosen frequency generated to carry data, often used for long-distance transmissions. A carrier signal does not convey any formation until the data is added to the signal by modulation, and then decoded on the receiving end by demodulation.

Client Application:-

1. In OLE (object linking and embedding), the application that starts a server application to manipulate linked or embed information.

2. In dynamic data exchange (DDE) conversation, the application that accepts the pasted link.

Client/Server architecture:-

A computing architecture that distributes processing between clients and servers on the network. Clients request information from the servers. The servers store data and programs, and provide network-wide services to clients.

Closed Architecture:-

A design that does not allow for easy, user-supplied additions. This term is often used to describe some of the early Macintosh computers, which did not allow easy expansion of the system with add-in cards. Closed architecture can also refer to a computer design whose specifications are not published or generally avertable, making it impossible with the computer.

CNA:-

Abbreviation for Certified Novell Administrator. A Novell certification program for network administrators responsible for the day-to-day operation of a network.

Coaxial Cable:-

Abbreviated, coax, pronounced "co-ax". A high capacity cable used in networking that contains a solid inner copper conductor surrounded by plastic insulation, and an outer braided copper or foil shield. Coaxial cable is used for broadband and baseband communications networks (and for cable television), because the cable is usually free from external interference and permits high transmission rates over long distances.

Communications Protocol:-

1. A standard way of communicating between computers or between computers and terminals. Communications protocols vary in complexity, ranging from Xmodem, a simple file-transfer protocol used to transfer files from one PC to another, to the

Seven-layer ISO/OSI model used as the theoretical basis for many large, complex computer networks.

2. A hardware interface standard, such as RS-232-C.

Concentrator:-

A repeater or hub that joints communications channels from several different network nodes. Concentrators are not just simple wire-concentration centers, but also provide bridging routing, and other management functions.

Congestion:-

An excessive amount of traffic on the network, causing messages to be blocked for long periods of time and adversely affecting network performance.

Connectionless Transport Protocol:-

Abbreviated CLTP. An Open Systems Interconnection (OSI) protocol that provides end-to-end transport data addressing and error correction, but does not guarantee delivery or provide any flow control. CLTP is the OSI equivalent of the UDP (User Data-gram Protocol).

Console:-

Sometimes abbreviated con. The monitor and keyboard from which the server or host computer activity may be monitored. Certain operating system commands and utilities must be executed from the console device; they will not operate from a work-station. In some systems, the console is a virtual device that can be invoked from any workstation by a network administrator with the appropriate rights and privileges.

Crosstalk:-

In communications, interference from a physically adjacent channel that corrupts the signal and causes transmission errors.

Customer Information Control System:-

Abbreviated CICS. An IBM-mainframe communications control program that manages transaction processing in IBM's VM and MVS operating systems. It also provides password security, transaction logging for backup and recovery, and an activity log that can be used to analyze session performance, as well as facilities for creating, using, and maintaining databases.