Two-way paging system having reverse channel message frequency authentication

DETAILED DESCRIPTION A method of modifying reverse channel messages in a two-way paging system to authenticate reverse channel messages is disclosed.
The intended frequency of the reverse channel message is converted into a unique binary integer.
The binary integer is used to modify a checksum in the reverse channel message so that the checksum is now dependent upon not only the message contents but also the intended frequency of the reverse channel message.
When received by a paging receiver of the paging system, an identical calculation takes place and if the modified checksum transmitted with the reverse channel corresponds with the calculated checksum, the message is authenticated.
Otherwise, the reverse channel message is rejected.
In another aspect of the present invention, the checksum is calculated by means of a cyclic redundancy check.
Further, the checksum is exclusively-ORed with the binary integer.