PL Codes

[cohenner5377]

Working on a project... can someone define what PL is, what it stands for, and how it works?

Realize there is a lot in this question... thanks for the help!!

David
MAR018

 

[ka3jjz]

PL stands for Private Line; this is a Motorola name for CTCSS and is known by several other older names, such as Channel Guard.

Basically what happens is that a subaudible tone is transmitted along with the signal in order to access or open repeaters or receivers. In the ham world, PLs are often used to access repeaters and help keep down any interference from other users on the same frequency (amongst other uses).

Here is a page that lists many of the possible values, though I don't think it's quite complete, it's a good place to start...

http://www.wpascanner.com/tones.htm

73s Mike

 

[ericcarlson]

http://www.radioreference.com/apps/wiki/index.php?title=CTCSS
http://www.radioreference.com/apps/wiki/index.php?title=DCS

-Eric

 

[ka3jjz]

http://www.radioreference.com/apps/wiki/index.php?title=CTCSS
http://www.radioreference.com/apps/wiki/index.php?title=DCS

-Eric

Good links, Eric, though I'd take issue with the statement that there are no code number assignments to each tone; Motorola has had its own cryptic number/letter combination for years, and I know several public service agencies use them.

73s Mike

 

[ericcarlson]

Yes, Motorola does have their own codes for certain tones, a modified version of the EIA codes. You can always update the Wiki to add or clarify information, that's what it's there for.

The Frequently Asked Frequencies page has the EIA, Motorola, Icom and ham codes.
http://www.strongsignals.net/access/content/faf.html

-Eric

 

[Spleen]

When you've been doing this listening stuff for too long, you can actually hear the subaudible tone, though you don't realize it until you hear another transmission immediately afterwards on the same frequency (Amtrak).

Sort of like visiting the U.K. and watching a TV there...most of us Colonists notice the slower scan speed of their TVs because we've never seen anything but ours most of our lives, but they have no idea...