a catv network distributing signals below 860 mhz is modified with a secondary transmission bi - directional capability above 860 mhz by adding filters to separate modified mobile - communications frequencies from typical catv services . catv subscriber termination points function as extremely localized ultra - miniature cell sites within a building . multiple cellular networks and possibly multiple providers are simultaneously accommodated over a catv network . the modified network simultaneously handles traffic in combinations of known cellular air interface standards such as : umts , gsm , tdma , cdma and pdc . cellular mobile radio terminals do not have to be modified . signals traverse on non - utilized catv frequencies . catv active elements are modified , and new components are provided . a cable mounted cellular adapter at the catv outlet acts as a transmit / receive unit and frequency translator for the cellular signals .