Cellular - CDPD (8)

The Intermediate Systems (IS) and Fixed-End Systems (FES) comprise the fixed network. These are off-the-shelf products which are "invisible" to the mobile network. IS's are routers which direct the packets to the correct location. FES is a general lump term used to describe the different possible destinations of the packets. FES's include external computer networks (such as campus networks), administrative servers, and network accounting servers, as well as many other examples.

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