A simplified Mobile Subscriber Equipment deployment diagram.
Mobile Subscriber Equipment was first fielded to the Army Signal Corps 13th Signal Battalion, 1st Cavalry Division in February 1988. This first-generation MSE system featured phones for both stationary and portable use, fax capability, and channels reserved exclusively for data. Soldiers dialed a fixed number by referring to a directory, similar to a phonebook. MSE software automatically located the desired party anywhere within the network—created by antennas and switching equipment stashed within mobile communications trucks—and connected the call. No manual routing or switching was required. In the event of damaged or overloaded circuits, MSE employed a technique called flood search routing that polled the system for an available circuit and dynamically routed the call around any glitches in the network. MSE also supported now common calling features like call forwarding and early digital or “packet-based” voice communications. In 1991, Mobile Subscriber Equipment would endure its first trial by fire.