Abstract: Requesting (transmitting) subscriber units may immediately begin transmitting an information signal over an assigned communication channel. Receiving subscriber units immediately unmute their speakers and monitor the assigned communication channel and attempt to detect a code, which indicates that they are monitoring the correct communication channel. At the central station (repeater), the information signal may be immediately repeated, unless an interference signal is present. In this way, the information signal may be rapidly disseminated (repeated) to improve subscriber access time, while providing assurance that the receiving subscribers will not receive a noise signal or the interference signal.

Abstract: A high-frequency dielectric ceramic compound having a perovskite-type crystal structure comprising a chemical composition substantially represented by the formula (Sr.sub.x Ca.sub.y Mn.sub.z)TiO.sub.3 in which 0.98<x+y+z<1.02, 0.34<y<0.4, and 0.0075<z<0.0015, and possessing a non-linear temperature coefficient is set forth. A method is presented for utilizing the compound to formulate a high-frequency dielectric material, the formulated material being particularly suitable for providing filters and related applications with a relatively low resonant frequency temperature coefficient.