A Pager tone in most cases Two-Tone are alert tones sent of the radio to alert a radio or pager.
PL tones (generically referred to as Continuous Tone Controlled Squelch System – CTCSS) and Digital PL codes (generically referred to as Digital Tone Control System – DTCS) are encoded with the voice audio at all times during transmission, and are used to control repeaters, exclude unwanted or uninvited traffic throughout the Public Safety, business, amateur and GMRS two-way world.