Abstract: In a multi-site communication system, a communication unit (106) transmits a communication request (208) that includes information identifying the sites (100 and/or 101) where the user desires to communicate with members of his user group. Communication resources are allocated (308) using the communication request and current resource allocation for the user group.

Abstract: A central controller of a communication system network may more efficiently expand an audience of a communication in the following manner. When a communication unit of a first communication group within a first communication system transmits a request for service, the central controller determines whether the audience of that predetermined communication is to be expanded. When the audience of the predetermined communication is to be expanded, the central controller combines at least part of at least one other communication group with the first communication group based upon a predetermined grouping arrangement. Having combined the groups, the central controller processes the predetermined communication among the communication units in the first communication group and the communication units in the at least part of the least one other communication group.

Abstract: In a trunked communication system with at least two communication sites, a call hand-off mid-call may occur when a mobile radio (109) moves from the coverage area of one site to the coverage area of another site. This second site may not have any communication resources available for this hand-off, and the radio (109) is issued a busy message. With user selectable site switching, the user may enter into the radio (221) the desire to return to the previous site, and the radio moves to the previous channel to continue (229) receiving the call.

Abstract: An improvement in an analog oscilloscope for an automotive ignition analyzer is disclosed. The improvement is a short store circuit which enables substantially complete display of the secondary coil voltage, including the peak amplitude of the firing line voltage.

Abstract: Various improvements in an analog oscilloscope for an automotive ignition analyzer are disclosed, including, among others, a short store circuit which enables the full amplitude of the firing line voltage to be displayed and a sweep trigger circuit which correlates engine speed and sweep length.