in a code division multiple access system a dispatch call is established between two mobile units and . the system includes a cdma 2000 system providing for the dispatch data services . this requires that messages and bearer traffic are processed by radio link protocol . the cdma 2000 system supports the fch and dcch channels . if the speaker &# 39 ; s forward link is link limited , , then a dcch channel is assigned to the speaker , . if the speaker &# 39 ; s reverse link is link limited then a fch channel is assigned to the speaker . in addition if there is a low battery level of the speaker , an fch channel is assigned to the speaker , . when the speaker changes , , the fch and dcch channels for the speaker and listener are switched dynamically , .