Multiple frequency message system

A multiple frequency transmitter for transmitting coded message signals on at least two channels in a plurality of geographic areas, comprising:

• channel identification means for generating channel identification information;
• message accepting means for accepting and generating a formatted message;
• timing means generating a periodic transmitter time interval;
• and
• coded message formatting means coupled to said channel identification means and to said message accepting means for combining said channel identification information with said formatted message to obtain said coded message signals, said coded message formatting means further coupled to and responsive to said timing means,
• whereby said transmitter transmits said channel identification information at least once during each of said periodic transmitter time intervals.

A receiver for receiving transmitted coded message signals on at least two channels, said coded message signals including channel identification information, comprising:

• detecting means for detecting transmitted coded message signals;
• decoding means responsive to said coded message signals for decoding said channel identification information;
• and
• channel selecting means responsive to said decoding means for maintaining said receiver operation on the first channel when said decoded channel identification information is the same as predetermined channel identification information, said channel selecting means further including timing means generating a periodic receiver time interval during which said channel identification information must be decoded.

A method for selecting the channel on which a receiver having first and second channels operates to receive transmitted coded message signals, said transmitted coded message signals including channel identification information, comprising the steps of:

• presetting said receiver to said first channel wherein said receiver can detect and decode said transmitted coded message signals including channel identification information;
• correlating said channel identification information to predetermined channel identification information stored within the receiver;
• maintaining said first channel at which said receiver will operate in accordance with the results of said step of correlating when said channel identification information received is the same as said predetermined channel identification information;
• selecting said second channel when said channel identification information is not the same as said predetermined channel identification information;
• and
• periodically rechecking the results of said step of correlation to determine when said selected channel should be changed.

A multiple frequency transmitter for transmitting coded message signals on a plurality of channels in a plurality of geographic areas, said transmitter including at least one common channel between said geographic areas, comprising:

• channel identification means for generating channel identification information;
• message accepting means for accepting and generating a formatted selective call message;
• timing means generating a periodic transmitter time interval;
• and
• coded message formatting means coupled to said channel identification means and to said message accepting means for combining said channel identification information with said formatted selective call message to obtain said coded message signals, said coded message formatting means further coupled to and responsive to said timing means,
• whereby said transmitter transmits said channel identification information at least once during each of said periodic transmitter time intervals.

A receiver for receiving transmitted coded message signals, said coded message signals including both channel identification information and selective call messages, on at least two of a plurality of channels, at least one of said two channels being the common channel between geographic areas, comprising:

• detecting means for detecting transmitted coded message signals;
• decoding means responsive to said coded message signals for decoding channel identification information;
• and
• channel selecting means responsive to said decoding means for maintaining receiver operation on the first channel when said decoded channel identification information is the same as predetermined channel identification information, said channel selecting means further including timing means generating a periodic receiver time interval during which said channel identification information must be decoded.

A method for selecting the channel on which a receiver having at least two channels selected from a plurality of channels, one of said channels including the common channel between a plurality of geographic areas, operates to receive transmitted coded message signals, said transmitted coded message signals including channel identification information and selective call messages, comprising the steps of:

• presetting said receiver to a first channel of said two channels wherein the receiver can detect and decode said transmitted coded message signals, said transmitted coded message signals including channel identification information;
• correlating said channel identification information with predetermined channel identification information stored within said receiver;
• maintaining said first channel of said two channels on which said receiver will operate in accordance with the results of said step of correlating when said channel identification information received is the same as said predetermined channel identification information;
• selecting said common channel of said two channels on which said receiver will operate with the results of said step of correlating when said channel identification information is not the same as said predetermined channel identification information;
• and
• periodically rechecking the reults of said step of correlation to determine when said selected channel should be changed.