A CSU sits between the digital line coming in from the central office (i.e. a T1) and devices such as channel banks or data communications devices. A device used to connect a digital phone line (T1 or Switched 56 line) coming in from the phone company to either a multiplexer, channel bank, or another device producing a digital signal. You can buy your own CSU or rent one from your local or long distance phone company.
(1) In the US, data transmission equipment to repeat the signal from the carrier and ink to CPE. Vendors add value to CSUs by adding performance monitoring and management. (2) In Europe, CSUs are sold for their value features like diagnostics and performance monitoring. The basic repeating function is prd in the NTU (networking terminating unit). CSUs monitor quality on El, E2 or E3 circuits in terms of transmission and line loading. A CSU is a device found on digital links that transfer data faster than modems but does not permit dial-up functions.
A device used to connect a digital phone line coming in from the phone company to network access equipment located on the customer premises. A CSU may also be built into the network interface of the network access equipment.
A CSU is a device that interfaces customer T1 (or E1) equipment to a carrier's T1 (or E1) service. At its most basic level, a CSU performs certain line-conditioning and equalization functions, and responds to loopback commands sent from the central office.
(CSU) The first device encountered by a T1 line entering a facility. The primary function of the channel service unit is to protect the equipment beyond it from damage due to disturbances on the T1 line and regenerate the signal to meet T1 specifications.