PL & Courtesy Tones

How the Dual PL, Link/Local System works:

Virtually all C.A.R.L.A. systems (unless noted otherwise) have two input PL's, the Link PL and the Local PL

If you use the Link PL, your audio is carried over the entire network of repeaters, and you will be able to hear the audio from any other repeaters in the network currently in link mode. If you wish to have a local conversation on the repeater just use the Local PL. Your audio will come out only on the local system and you will not hear link audio coming from other repeaters in the network. When you finish your local conversation, the link will automatically re-establish itself in several seconds.

A couple of things to keep in mind:
  1. If you pause for an extended time during your local conversation the link audio may come back. Just key up with the Local PL to mute any incoming link traffic and continue your local conversation.
  2. Remember, if there is a conversation in progress elsewhere on the network, you will not interfere with it if you hold a conversation on the repeater while using the Local PL.
  3. If you want link audio to come back right away just "kerchunk" the repeater you're on with the Link PL.
  4. There is a different courtesy tone for local traffic and incoming link traffic so you'll be able to distinguish from which direction the audio traffic is originating.
We've also prepared a visual guide to help explain the operation of the Dual PL system:

C.A.R.L.A. Dual PL Guide (PDF) (Opens in a new window)


What the various Courtesy Tones mean:

The C.A.R.L.A. system uses several different courtesy tones to help indicate to our users what is going on on the repeater that they are listening to. Among other things, this plays an important part in helping our users to audibly identify which PL, Link or Local, they are using. Below we've posted some examples of courtesy tones you might head on the system (you will need Flash installed in your browser to listen to these samples).

Link Courtesy Tone: If you were using the Link PL, this is what the repeater's courtesy tone would sound like:

Local Courtesy Tone: If you were using the Local PL, this is what the repeater's courtesy tone would sound like:

Link Courtesy Tone, Second Repeater: Sometimes there is a second repeater at the same site (this is the case with System 5 and System 35). In that case, the Link PL courtesy tone would sound a little different:

From the Network: When you are using the Link PL, not only will you hear a Link Courtesy Tone as above, but you should also hear this next courtesty tone. It is an indication that the repeater heard the "kickback" from its connection to the network. This is a normal indication. If you don't hear this, that may mean that the link is down. The tone:


Examples in Conversation

Now let's tie it all together. Here's an example of a conversation where two users start off on the Link PL on the same repeater, then switch to the Local PL on that same repeater:

Here's what the conversation above would sound like from the perspective of someone listening on a repeater elsewhere on the network (of course, once they went to the local PL, you wouldn't hear them anymore):

Now, here's an example of what you might hear if you were listening to a conversation between two repeaters at the same site, whilst monitoring one repeater or the other.


Older Courtesy Tones

Originally C.A.R.L.A. used the following courtesy tones. There are only a few repeaters out there that still use these courtesy tones, but just in case you happen to run across them, here they are.

Old Link Courtesy Tone: If you were using the Link PL, this is what the repeater's courtesy tone would sound like:

Old Local Courtesy Tone: If you were using the Local PL, this is what the repeater's courtesy tone would sound like:


Please note that although this covers the courtesy tones you will hear 99% of the time, you may occasionally hear other courtesy tones not listed here, that usually exist for a specific purpose. As always, listening before and during your conversation will help you learn what each courtesy tone means.