Selcall

Selcall is an abbreviation for Selective Calling. Your radio will have a microprocessor in it or Integrated Circuit that will generate audio tones at within a certain time period, normally being around 30 to 40ms. The receiving radio would also be equiped with similiar equipment that decodes the tones. Both the transmitter and receiver radio will have a number programmed into it so it triggers an alert to the operator when a certain number is received. By using this method, one can 'selectively call' a friend without saying a word.

Some Radios will have different tones and different respective receive trigger numbers, and will be capable of sending different tones or maybe fully programmable numbers. However, some radios only have a send button and one number programmed to be sent and one to receive with no operator changes.

Selcall can also be arranged in such away that you can call a group of people as well. There are different tone sets that selcall can use. Each number is reprsented by a tone of different audbile frequency.

Selcall tones and sequences can also be generated easily by your own PC. The PC speaker can be used to generate tones at the speed you desire.

Wikipedia SELCALL reference

Updated September 7th, 2007