The article notes that new communication techniques developed from the problem of running out of frequency spectrum. The demand for room on the radio dial is pushing land mobile radio services into higher frequencies. The move is into the 800-MHz band, and that band is filling up in some areas. Another problem is that the FCC authorized commercial ambulance services to use UHF for nonemergency use. Digital microwave systems need to be utilized to improve system efficiency. The article describes various advanced trunking systems, such as the new 800MHz Motorola and GE-NET 900, for the newly opened 900 MHz band. Other systems described are the LTR 8620, CLEARCHANNEL LTR 8655, and the IC-UI8 (UHF) and IC-H18 (VHF).