L

line device

A physical channel composed of a telephone line and the hardware to control it such as a fax board, a modem, or an ISDN card. The simplest kind of line device corresponds to exactly one telephone line.

line device class

A device-independent representation of a physical line device, such as a modem.

local loop

The part of the telephone network between the telephone and the telephone company's central switching office. Within this loop, human speech from a household telephone is usually transmitted in analog format, and the digital data from a computer must first be converted to analog by a modem. Digital networks are gradually replacing analog in the local loop.