Repeater controller that doesn't mute DTMF?

[Jonathan KC8RYW]

Anyone know of a repeater controller that doesn't mute DTMF? Every repeater controller marketed to hams I've seen does. Now how are people supposed to do DTMF paging, if the repeater doesn't pass it thru?!?

[Doug]

Hello Jonathan,
I've got an s-com 7k on my ham repeater and they give you the option in the controller to either mute dtmf or pass it. We've got a linked system and one of the repeaters is hooked up with IRLP which can be brought up from any of the remote links by passing dtmf through the controller and it works without fail.
Doug

[Big BOB]

Most all of the repeater controllers now days will let you pass DTMF. There is a command to either turn it on or off. Some have a digit such as the # you hit first then all tones after that pass thru.

[alex]

on our ham repeater you press * and then the repeater controler ignores the DTMF. I think you can also program most of them to not mask it. most controlers mask the DTMF signal so that people with decoerds can't get the control codes, which makes sense. Usually you can't hear someone on the input to really decode anything.

-Alex

[Jonathan KC8RYW]

Bah... any sensitive repeater control should be over an auxiliary link, a land-line phone, a web interface, or a combo of them all.

The security of landline phones can't be beat. If someone taps the line, then they committed a big offense, wiretapping, and can be tried in the legal system, not just at the ham group meeting.

Programming all DTMF pages with a * at the beginning is silly.

The repeater users use the repeater more then the trustee fiddles with it. Why are they setup for admin mode all the time, and user mode as an option?

Why not enter a code, BEFORE entering the secret codes, that stops DTMF from being passed to the output? Why? Because it would make too much sense.

[ARZ902]

The Linkcomm controllers can turn on or off the DTMF mute.

Dennis

[d119]

Programming DTMF pages with a * is silly, eh Jonathan?

What happens when you bring up your phone patch with some cracked out jammer listening with his Optoelectronics DTMF decoder, and he gets your patch code because the repeater doesn't mute DTMF?

Well in my case, if someone got my patch code and decided to call 911 at 3:30AM and scream into the radio, I'd have some pretty pissed off law enforcement people at my door, most likely with guns out and the battering ram waiting.

Sound far fetched you say?

It happened once in a neighboring city. The local ham club runs their interconnects over 420MHz links to the ground in various places in the County to avoid toll charges. The DTMF on those 420MHz links is not muted because you've obviously got to get the patch information from the hill to the ground. Different codes for different parts of the County, it's all home-brew. Someone thought it'd be funny to call 911 and report a rape in progress on the telephone interconnect at 3am, after grabbing the patch code off the 420MHz link using a DTMF decoder. Shortly there after, the Sheriff's Office, responding code 3 knocked the guy's door down and held him at gunpoint because the ALI on the 911 console showed his address (where the telephone line connected to the interconnect link was).

So block 911, 411, and 0 calls you say?

Well, 411 is blocked. But block 911? It defeats the purpose of having an interconnect in my case. It's there for emergencies, what good is it if 911 is blocked? 0 calls I allow for my own maintenance purposes.

DTMF mute is an invaluable security measure, and I can't believe you don't see that. It puts you out of your way to just add 1 stupid digit to your paging code? Yeah. I SERIOUSLY doubt most hams would even put up with listening to DTMF paging codes over the air all the time. I'd kick anyone doing that on my repeater off until they get a clue. (Modat and MDC are acceptable )

Granted someone could just listen on the input to the repeater, but chances are they wouldnt be close enough to hear you anyway if you do all your controlling from a portable like I do.

As for links and stuff like that, well, control links require radios, antennas, feed line, and COORDINATION (at least where I live), which are hard to come by. Sometimes you need to control the repeater and you aren't near a phone. Phones don't usually have the ABCD keys on them either (hello fellow DSN/AUTOVON users ), so sometimes you dont have any choice BUT to control on the input.

Try and look at all of the points of view, for once.

~119

[Jonathan KC8RYW]

d119, I am glad that you have your own opinion on the matter.


I am under the presumption that repeaters were designed to
actually repeat. garbage in = garbage out. DTMF in = DTMF out. Good quality MDC1200 data in = good MDC1200 data out. Low level voice in = low level voice out.

The only real exception to this rule would be +/- 6 KHz audio in = limiting down to +/- 4 KHz output. And, the requirement of a valid tone, if required.


I'm sorry that someone abused a telephone interconnect. We all know that making false distress calls is not protected by the First Amendment, and is punishable under our legal system.


My suggestion about using a code to mute DTMF on the output comes into play about entering your code. It's just one more code before entering the real code, but it certainly does the job.


I suppose QC-II paging could be used in my application... but, alas, it would probably annoy repeater users more then quick DTMF digits. Of course, that is if they even know what QC-II is at all.


Truth to the matter is... just because one CAN do remote control over the air, doesn't mean that one SHOULD do it.


Repeaters first priority is to increase mobile coverage area, not make phone calls on. If one really wants an emergency phone patch, then one should buy a phone.

[nmfire10]

Anywhere around here my Cell Phone has no service, the 2 local repeaters DO. In fact, I have USED it for that. There is a major valley down the road from here and on my home from work in snow storm, a head-on occured right in front of me on the downhill. Cell phone... HA, yea right. But the repeater had DFQ Coverage. Luckily, I was conversing with someone at the time and I just asked him to call 911 for me while I got out and started doing my thing. It worked perfectly, actually I think several people that were just monitoring and not chatting called it in for me too.

[alex]

I've used the 911 patch 2-3 times before on a repeater in boston. First time was for a car fire, another time was for an accident on my way to work, and the last was when I got stuck in the right lane of traffic with no shoulder, and no one was around to call for me. I do now have a cell phone, and since I'm a local 911 provider, using it or 911 access is simple enough, i just asked to be transfered to the respective dispatcher.

Most repeaters will not dial 911 - simply because they cover more than just the town. most the ones I know of have autopatch numbers for each county OEC's that it coveres, along with state police. The one in boston calls an 800 state police #, and then you get either bounced to local for your calling area, or they tell you help is on the way, and dump the job card to someone elses terminal.

-Alex

[APCOMAN]

Try a Commspec TP-3200. They work just fine.

[d119]

The problem with mobile phones where I live is that the 911 center that answers is the Highway Patrol. Most of the time, be it 5:00PM or 3:30AM, you end up waiting on hold for an incredible amount of time before someone answers. Sometimes it's more efficient to just get a 911 line on the phone patch, then ask the call-taker that answers to transfer you to the appropriate agency. If you state who you are (and have any credentials), they generally don't ask questions.

I've always found a 911 interconnect to be much more useful than one made over a mobile phone.

[nmfire10]

If the cellular communications mogouls would get off their buts and finish implimenting the Wireless E-911 phases that were supposed to be done years ago, that wouldn't be a problem. Right now, if you call 911 on a cellphone in Madison, it is answered by the Regional 9-1-1 center in Westbrook. Once they finish the Wireless E-911, the phone system will know where you are and connect you to the proper PSAP. I'm not holding my breathe on it though. It costs money, so it will be put off as long as possible, regardless of people's safety.

[Will]

Yes, we have had certain persons getting the DTMF access codes to the community/multi-user tone pannels in comercial repeaters and changing the codes, turning on and off users. We had to remove the DTMF pass thru circuits but the bad guys still got the codes by listening on the rptr input, so we had to take DTMF access out of the panels and they could only be programed locally by RS232/M8. Most pannels will let you activate or disable DTMF repeat remotely on a per user basis. My ham 440 MSY repeater would not repeat the DTMF after the first valid acces DTMF digit, and when in the phone mode, so the number you dialed was semi secure.

We are fortunate in So. Cal. to have several repeaters, one on VHF HAM that is monitored 24/7 for emergencies. On UHF, we have several GMRS rptrs that are monitored 24/7 by a REACT member who can handle emergencies notification(s). The last thing I want to do is try and dial some DTMF codes and then a number in an emergency situation, I'd rather grab the mic and report, then I can be available to help IF nessary or needed.