Data service unit

From Hill2dot0

A data service unit (DSU) converts the DTE’s signal to the form required by a digital services circuit. For example, to interface to a T-1 service, the DSU needs to convert from bipolar EIA-232 or V.35 signaling to the AMI or B8ZS signaling used in T-1. In addition, the DSU creates control signals for the host and provides timing recovery and synchronous data sampling. DSUs are most commonly offered in a single unit that also provides CSU functions. There are DSUs for DS-0, DS-1, or DS-3 service.