Abstract: A selective call receiver (111) has a first mask (134A) stored within the selective call receiver (111) indicative of a first period of reception for receiving a transmitted communication signal (99) having a plurality of packets (100). Each of the transmitted packet (100) has message information (110). An identifier (106) identifies the packet (100). The control signal (108) is representative of a second mask (134B) indicative of a second period of reception. The second mask is compared with the first mask for determining the second period of reception of the selective call receiver (111). A correspondence between the first and second masks determines whether to change the first period of reception of the selective call receiver (111) for receiving at least one additional packet.