Line driver
Line driver may refer to any of the following:
1. Alternately called a short-haul modem or limited-distance modem, a line driver extends transmission range between terminals and computers on private lines or networks. It can extend a signal that often covers only a few hundred feet to spans of several miles. Line drivers play an important role in connecting various devices, like POS (point-of-sale) terminals and machine tools, to a host computer.
2. With analog audio, a line driver is a device that takes a weak audio signal and amplifies it. The boosted line-level signal output is better equipped to travel through cables. Essentially, a line driver ensures the audio maintains the highest possible sound quality and richness while traveling from the source (CD player) to the output device (headphones).