A pager based information system (2) is used to transmit both conventional individual and group messages (using pager capcodes (76) for pager identification) and three types of unconventional multi-recipient (M-R) messages (using database ID's (68), multi-level group (MLG) ID's (78) and M-R group ID's (46)), all using the conventional POCSAG pager transmission format. Operation of the pager (6) is software controlled through the use of a microprocessor (8) and RAM (16); auxiliary chips are not needed because of the relatively slow transmission speeds. Authority to receive the M-R messages is provided at the time of manufacture (electronic serial number (ESN) (74)) or via broadcast (database ID's, MLG ID's and group IDs). Database messages are stored in pager RAM in a hierarchical or tree structure. The software controlled pagers permit the over-the-air modification of the operation of selected pagers, such as the addition or deletion of group IDs and the change in the tree structure of the database area of RAM (typically through the transmission of database messages). The pager includes a real time pager clock ( 106) which is updated by pairs of broadcast time messages, the second having a time correction for the first.