if the timer has not expired then the steps in the flow diagram are repeated beginning with step 206 if word synchronization is acquired on the paging channel in decision 213 the messages are read in step 214 and the first part of the serving area 39 s received system identification number sid1 obtained from reading the paging channel is compared with the sidm obtained while reading the messages on the dedicated overhead channel in step 209 if the sid1 does not match the sidm as determined in decision 215 the process returns to step 205 and checks to see if there is time remaining on the timer if the timer has not expired then the steps are repeated beginning with step 206 if the sid1 matches with the sidm then at step 216 the pager unit compares the sidm derived from the messages in step 209 and the system identification number for the home service area sidh which is stored in the number assignment module nam in the memory section of the pager unit if these match the pager unit is considered to be in the home area and the process advances to step 301 shown in fig3 if the sidm does.