[arm-allstar] wireline tone control of repeater

[Brian Swann]

Doug,

The way I read his request, he's looking for Tone Remote Control (TRC)
which is an older analog standard for commercial radios. Typically a normal
channel 1 keyup is 120ms of "High Level Guard Tone", which is 2175hz,
immediately followed by 40ms of the F1 "Function Tone" which is 1950hz.
Then the voice is gated through, and a continuous "Low Level Guard Tone" at
a level of -30db (compared to full voice modulation) is sent along with the
voice. The LLGT keeps the transmitter keyed. The transmitter drops out when
the LLGT disappears.

By using different function tones, you can change channels, or transmit PL
stripped, or do other functions. Most base stations were fairly simple and
didn't implement too many different functions.

I don't think this is implemented in Hamvoip, although it might be. I don't
think it would be very difficult to add in. The advantage would be that a
lot of commercial surplus base stations speak this "language" by default.

More info in the Wikipedia article https://en.wikipedia.org/wiki/Tone_remote

Tone remotes send commands to a base station using *function tones*, a
series of two tones in sequence. The first tone is 2,175 Hz and is 100-300
milliseconds in length.[6]
<https://en.wikipedia.org/wiki/Tone_remote#cite_note-6> The most common
second tone is 1,950 Hz. The most commonly used tone sequence in tone
remote controls is the channel 1 transmit command. The default for this
command consists of a high-level 2,175 Hz followed by a lower-level
1,950 Hz. A continuous, low-level 2,175 Hz tone follows. Voice is
multiplexed over the tone. So long as the 2,175 Hz tone is present, the
transmitter remains on. An audio notch filter
<https://en.wikipedia.org/wiki/Notch_filter> removes the 2,175 Hz low-level
tone from the actual transmit audio. General Electric Mobile Radio called
the high-level tone, '"Secur-it tone", and called the low-level tone "hold
tone." In the industry, the low-level continuous tone is often called,
*low-level
guard tone*. The low-level tone is present at the same time as transmitted
voice.

Brian
n1bs

On Tue, Jan 28, 2020 at 5:53 PM "Doug Crompton via ARM-allstar" <
arm-allstar at hamvoip.org> wrote:

> Chris,
>
>  I am not completely clear on what you want to do but the answer is yes you
> can control a capable rig either through hardware or CAT control to change
> frequency and other things using DTMF. See the howto on this at the
> hamvoip.org web page which explains how to use GPIO bits to control BCD
> channel changes on capable radios. Hamvoip also has hamlib installed and
> using rigctl commands you can control many radios. It is up to the user to
> implement this. Do  rigclt -l    at the Linux prompt to see all the
> currently controllable rigs.
>
>
> *73 Doug*
>
> *WA3DSP*
>
> *http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*
>
> On Tue, Jan 28, 2020 at 11:09 AM "c b via ARM-allstar" <
> arm-allstar at hamvoip.org> wrote:
>
> > does allaratlink support tone control of a station?
> >
> > for instance using 2175 (switching to low level)  to PTT and using
> > different tones to change channel?
> >
> > or at least the ability to send the correct tone to change channels via
> > sending DTMF to the to allstar and then allstar sending the tome out the
> > URI to the station?
> >
> > the application would be a continuous duty remoter using a mastr iii and
> > making it multi channel by sending the correct tone to switch channels.
> >
> > thanks
> >
> > Chris
> > _______________________________________________
> >
> > ARM-allstar mailing list
> > ARM-allstar at hamvoip.org
> > http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
> >
> > Visit the BBB and RPi2/3/4 web page - http://hamvoip.org
> >
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