Kenwood 2 tone calling, how is it supposed to work, what is the use case?

[K7HUT]

Hi all,

After alot of experimenting, with a TK-3180 (no dtmf keyboard, just the 4 PF keys on the front), I was able to configure a 2 tone calling sequence, and figured out after quite a while that you had to trigger the TX of those tones with a key press (so I programmed one of the PF keys to do this). In fact, the only way I could figure out that 2 tone sequence was ONLY sent by a key being pressed, was that I saw '2-Tone' was one of the PF key actions. Otherwise in no manual of any kind, post here, or youtube demo video, was it shown how 2 tone calling works, and why is it even a thing, what is its purpose?

Once I press the 2 tone PF key on the 3180, I hear those 2 tones come over to my UHF ham radio unit monitoring that frequency.

OK great, now I can send the 2 tones.

But what happens next? Now I sent the tones... when I press TX and send voice on that 3180 that just sent the tones, what happens at the properly programmed receiver? It first heard the right tones, and does it then open the audio monitor to all further carrier demods of audio? For how long does that go on?

I understand CTCSS is a continuous carrier, so as long as that proper CTCSS tone on tx and rx is configured, audio will pass from transmitting to receiving radio.

But with this 2 tone, it just happens at time t, then at time t+1 second,how long does the receiver audio stay monitoring the transmission? How does the receiving unit even know the transmission coming in is from the unit that originally sent the 2 tone sequence.

Or is the 2 tone just a way to send some kind of alert to a receiver that is configured to create an alert tone once it receives the proper 2 tone sequence?
Like an old school pager?

Sorry for these super basic questions, I recognize this is very old hat in the professional radio space, but I have exactly zero experience with configuring radios and the history of radio evolution in commercial, safety, public service sectors.

 

[Markb]

Hello. You pretty much nailed it. We use 2 tone at my agency for 2 things: fire station alerting and emergency fireground alerting.

For station alerting, the dispatcher sends a 2-tone sequence which the base station radio receives and in-turn opens the PA system and turns on interior lighting via relay. There is also an all-call tone sequence as well to alert all stations at once. The station alerting receiver timer resets after 2 minutes, PA speakers are again muted and the lights time out.

For fireground alerting, a given radio (TK-2180) can transmit the 2-tone sequence that will set off a loud alarm tone on the receiving radios and the urgent message can be transmitted once the air is clear. The speaker is never muted. It's basically a "Hey, pay attention to the following urgent message" alert. Usually this is for things like downed power lines or imminent building collapse.

The other main use for 2-tone is the ability to call a particular radio in a fleet and not bother other users. Not sure if this is ever used in business applications, but it is still found in public safety. It is fairly ancient technology nowadays (1950's era) and is slowly fading out.

 

[mmckenna]

Otherwise in no manual of any kind, post here, or youtube demo video, was it shown how 2 tone calling works,

If you have a legit copy of the KPG-89, the "help" button will give you some clues to it's function and how to set it up.
If you were a dealer, you'd have the "indepth manuals" that cover all this stuff in detail.

and why is it even a thing, what is its purpose?

MarkB covered it pretty well. Station alerting, radio alerting, paging, triggering outputs/remote controls, setting off vehicle horn alerts ("Hey, you've got a call!") lots of things it can be used for.

But what happens next? Now I sent the tones... when I press TX and send voice on that 3180 that just sent the tones, what happens at the properly programmed receiver? It first heard the right tones, and does it then open the audio monitor to all further carrier demods of audio? For how long does that go on?

Depends entirely on what you want it to do, and what you program it for.
It can do an audio alert to the receiver. You can set it up to do contact closures on the rear 25 pin to remote control just about anything you want.
And the various timers control how long it alerts for, how long it leaves audio open for, etc.

I understand CTCSS is a continuous carrier, so as long as that proper CTCSS tone on tx and rx is configured, audio will pass from transmitting to receiving radio.

It can, or using the reset timers, it goes back quiet until the next call.

We used this function for years to alert the fire station. Dispatch console would send out the 2 tone sequence. In the station, the radio would send a warble tone over the station PA, then the audio would open and the dispatchers would dispatch the units. Lights would turn on, etc. After about 5 minutes, we had it programmed to go back to quiet mode and wait for the next call.
We also had two channels set up on the radio. One was a "day" channel that would pump all received audio out through the station PA so they could hear it. The other channel was the "night" channel. That one would be set up to use the 2 tone alerts so they wouldn't have to listen to all the other stations getting paged out.

But with this 2 tone, it just happens at time t, then at time t+1 second,how long does the receiver audio stay monitoring the transmission? How does the receiving unit even know the transmission coming in is from the unit that originally sent the 2 tone sequence.

Look at the settings for "Auto Reset Timer".

 

[K7HUT]

Thanks very much, that explains alot.

I do have a legit copy (afaik, I paid for it) of the 89D sw, and I combed that Help file so many times, but still it never explained a complete sending and receiving use case or example. Also I have the User Manual, Programming Manual, Service Manual, the Function Reference Manual and others I downloaded off the net, but still no help really. These two replies are 100x more informative on this topic than all the official Kenwood stuff I could find.
Maybe there is a dealer only document that I missed finding on my search.

Thanks for the help.I am getting another TK-3180 that I can experiment with and set up various calling options on both radios, and see what happens on the other side. I really have no use case for this, as I am just a GMRS club member, but I want to understand the feature sets of these radios, at least for non trunking applications, and what is possible, what other information or signals can be sent and received.

Thanks again.

 

[mmckenna]

Thanks very much, that explains alot.

I do have a legit copy (afaik, I paid for it) of the 89D sw, and I combed that Help file so many times, but still it never explained a complete sending and receiving use case or example. Also I have the User Manual, Programming Manual, Service Manual, the Function Reference Manual and others I downloaded off the net, but still no help really.

Those in depth manuals are intended for shop techs that already have some technical knowledge about this stuff. It'll cover specific details about the radio/interfaces, but it's not intended to be a primer on 2 tone paging for those not familiar with it.
Probably some google searches on 2 tone paging, remote control, etc. would be a good place to start. When you have the basics down, the Kenwood in depth manuals will make more sense.

These two replies are 100x more informative on this topic than all the official Kenwood stuff I could find.
Maybe there is a dealer only document that I missed finding on my search.

Glad we could help.
The Kenwood in depth manuals for the TK-x180 series are:
FPRG - Field Programming Reference Guide
FUNC - Function Reference Guide
MOD - Modification Information Guide

The service manual won't be much help on the 2 tone stuff.
The user manual is pretty much useless. It give a very brief overview of what the radio will do, but -only- if the radio is programmed for it. I never give them to end users since it creates too much confusion.

Thanks for the help.I am getting another TK-3180 that I can experiment with and set up various calling options on both radios, and see what happens on the other side. I really have no use case for this, as I am just a GMRS club member, but I want to understand the feature sets of these radios, at least for non trunking applications, and what is possible, what other information or signals can be sent and received.

If you haven't purchased yet, I'd recommend getting the TK-8180 mobile. The 450-512MHz, non-H version has the necessary FCC Part 95 certification for GMRS use. The 8180 will have the rear 25 pin (DB-25) connector that will give you all the outputs. Those programmable inputs/outputs can be programmed to do different things with 2 tone.
You could program an input to send a 2 tone page to your hand held and sound a tone/alarm
You could send two tone pages from your hand held and trigger functions via the mobile (turn the coffee pot on before you get home).
A lot more flexibility….

 

[K7HUT]

Thank you kindly mmckenna, that is much appreciated.
I actually installed that exact TK- 8180 in my truck a few months ago. Coupled with the Comet 2x4nmo antenna, it's amazing (yes I drilled the damn hole!). I thought if I had 2 or 3 of the x180 radios, that somehow I could use that 2 tone or DTMF signalling to do something interesting, as long as they had that capability.

The idea of using the rear data connector is fascinating... be a nice to have a remote kill feature for my truck should it get stolen and be on the move (12vdc at the radio).

Programming the 8180 and 3180 from the same PC involves alot of switching cables, so I am getting a 2nd 3180 so I can basically quickly tweaks params (same cable on same PC indoors, as I live in hot Phoenix area) and see what happens at either end, with also an UHF open squelch ham handheld tuned to that freq to see what is being sent out that is audible.

Thanks again for the knowledge. I only found Google hit on 2 tone, and that was the history of commercial/safety radio on some vendors site, where they went from nothing to PL tones to all the way where we are today,so that's the first and only place where I started to discern the 2 tone was useful for an alert sound creation, ala old school pagers. I'll keep searching, but you got me on the right track now.

EDIT: now that I am Googling for '2 tone paging' per your comment above, now I have quite a few hits explaining the concept from different perspectives. I guess I was not adding the right word after '2 tone' before.

 

[K7HUT]

I found this page very helpful: Two-Tone Paging - Genave

I guess all this two tone and DTMF paging was built because TCP stacks and digital radio bit streams had not been invented yet LOL.
Was/Is two tone and DTMF signaling like this reliable to have public safety related events happen with certainty and feedback to the paging person/agency to know that the action took place?

 

[mmckenna]

I guess all this two tone and DTMF paging was built because TCP stacks and digital radio bit streams had not been invented yet LOL.

Pretty much. For what they wanted, things like 2 tone, 5 tone, DTMF, MDC600, MDC1200, FleetSync, etc. were all more than capable of doing what was needed.

Was/Is two tone and DTMF signaling like this reliable to have public safety related events happen with certainty and feedback to the paging person/agency to know that the action took place?

Yes. Two Tone paging is still heavily used in the fire service. Very common to have volunteer fire services with guys carrying analog pagers.
Usually the procedure was for dispatch to send the page, announce the call, and have the station answer back to confirm reception/acknowledge the call.

 

[K7HUT]

Got it. Pretty neat that this was reliable to the point that it's being used today, because it basically works reliably.
I guess there is so much hardware infrastructure installed base, that is working, that there is no urgency to go to some 100% digital protocol.
Very interesting.

I think when it comes time to integrate reading and acting on new sensors and activation solutions, that's when the switch to digital happens.

 

[KK6ZTE]

Got it. Pretty neat that this was reliable to the point that it's being used today, because it basically works reliably.
I guess there is so much hardware infrastructure installed base, that is working, that there is no urgency to go to some 100% digital protocol.
Very interesting.

I think when it comes time to integrate reading and acting on new sensors and activation solutions, that's when the switch to digital happens.

In a lot of the "fancy" TCP/IP based fire station alerting, the fallback for inevitable network failure is...you guessed it...2-tone alerting!

 

[mmckenna]

I think when it comes time to integrate reading and acting on new sensors and activation solutions, that's when the switch to digital happens.

Pretty easy to do with P25, DMR and NXDN to individual radios. But analog paging is cheap and gets the job done. Unication is the only one I know of that makes a P25 or DMR pager.
You start doing P25 alerting, and it always seems to go to everyone getting an expensive radio. Analog pagers are cheaper.

 

[K7HUT]

I am about to get a DMR radio and start playing with that soon.

I can see where 100% analog implementation does have a certain charm about it.
Minimal eqpt, less complexity, no setup of digital infrastructure/routing, don't care about internet downtime just need to keep that repeater powered up.