c with average and peak traffic parameters (e.g., LAN interconnection and internetworking ser- vices, LAN emulation, critical data transfer that requires service guarantees). Remote procedure calls, distributed file services, and computer process swapping and paging are examples of appli- cations that would be appropriate for ABR. access charge A cost assessed to interexchange carriers for access to the local exchange network. access concentrator A device that can be used to concentrate local subscriber lines and multiplex them over high-speed transport to another point in the network, creating a virtual access line A connection from the customer to the local telephone company for access to the PSTN, also known as the local loop; can also refer to the connection between the serving toll exchange and the serving office of the interexchange carrier used to access PSTN transport services. ACK (acknowledge character) A transmission control character transmitted by a station as an affirmative response to the station with which a connection has been set up. An acknowl- edge character may also be used as an accuracy control character. adaptive equalization Line equalization, sometimes known as impedance equalization, used for optimizing signal transmission to adapt to changing line characteristics. Glossary adaptive routing adaptive routing Routing that automatically adjusts to network changes such as traffic pat- tern changes or failures. address (1) A coded representation of the destination of data, as well as of its source. Multiple terminals on one communications line, for example, must each have a unique address. (2) A group of digits that makes up a telephone number. Also known as the called number. (3) In soft- ware, a location that can be specifically referred to in a program. (4) A name, label, or number that identifies a location in storage, a device in a network, or any other data source. address signals Signals that carry information that has to do with the number dialed, which essentially consists of countr