DESC: The TSU Series consists of T1 DSU/CSUs, multiplexers, and integrated access devices. It provides the industry's most flexible and reliable solutions for aggregating voice-only or voice and data services over a single T1. TSU solutions feature modular interface slots and a broad range of option modules. Over 30 modules have been designed to accomodate almost every combination of voice, video, data, and Internet applications over a T1 TDM circuit.