Originally Posted by kemmer
I was wondering if i put the PL's into the scanner, if the identifier numbers will show up? like 102 for car 102 and 161 for engine 161.
No Pl's are not used that way.
CTCSS (Continuous Tone Coded Squelch System) (PL) is a system that is used to avoid interference between separate agencies within close proximity to each other using the same frequency. Each radio for a particular agency is programmed with a CTCSS code so that only those radios can hear and talk with each other and not a neighboring agency.
The system involves an industry standard set of sub-audible tones for controlling radios and associated equipment. The sub-audible tone is added to the transmitted signal. The receiving radio is then set up to listen for this specific tone in the received and demodulated audio. If the matching tone is present, the squelch is opened up, allowing the audio to pass through to the speaker. If the tone is not present, then the radio remains silent, even though there is a signal on the frequency. This allows two or more agencies to use the same frequency (generally on a repeater), but not hear each other's conversations.
CTCSS is also called "PL Tone" and is the Motorola Proprietary name for CTCSS. Several other companies have marketed their own brands of CTCSS under different names including "Channel Guard", "Quiet Channel", "Quiet Mode", and "Private Mode".
DCS on the other hand stands for Digitally Controlled Squelch. It is also called DPL or Digital Private Line and Digital Channel Guard. DCS is a digital code that is sent to open the squelch just like the tone does in CTCSS.
Closest thing in a scanner is radio ID available on the newest GRE and Radio Shack scanners.