ADTRAN offers the industry's most versatile T3 termination solutions. The T3SU 300 multiport T3 DSU/CSU offers more interface ports than competing products, at an extremely competitive price. It offers a built-in HSSI interface and three optional expansion slots for up to three additional HSSI interface modules, single-port V.35 data modules, Quad DSX-1 modules for digital voice applications, or Quad Bridge Modules. The cards are field swappable, requiring no factory assistance to install.