The Litespan 2000 access product from dsc Communications Corp., Plano, TX, joins other dsc switching and transmission products in the Dallas-based gte`s network. Litespan is a sonet-based platform that provides a range of narrowband and broadband services. According to dsc, Litespan provides low-cost telephone lines for residential and commercial use and offers the ability to provision wide bandwidth services in the same plug-in channel unit slots.