In telecommunications, a channel bank is a device that performs multiplexing

Multiplexing

The multiplexed signal is transmitted over a communication channel, which may be a physical transmission medium. The multiplexing divides the capacity of the low-level communication channel into several higher-level logical channels, one for each message signal or data stream to be transferred...

 or demultiplexing of a group of communications channels, such as analog or digital telephone line

Telephone line

A telephone line or telephone circuit is a single-user circuit on a telephone communication system...

s, into one channel of higher bandwidth or higher digital bit rate

Bit rate

In telecommunications and computing, bit rate is the number of bits that are conveyed or processed per unit of time....

, such as a DS-1

Digital Signal 1

Digital signal 1 is a T-carrier signaling scheme devised by Bell Labs. DS1 is a widely used standard in telecommunications in North America and Japan to transmit voice and data between devices. E1 is used in place of T1 outside North America, Japan, and South Korea...

 (T1) circuit.

A channel bank may be located in a telephone exchange

Telephone exchange

In the field of telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls...

, or in an enterprise's telephone closet or enclosure where it "breaks out" individual telephone lines from a high-capacity telephone trunk line connected to the central telephone office, or the enterprise's PBX system.