[Asterisk-Users] dingotel - connect Asterisk to 2-way radio?

[Mark Phillips]

This has been round a few times.

The bottom line is that it's not doable with this product. The nearest 
solution is either app_rpt which requires a bespoke board to run the 
radio using * as a repeater controller with voip links or to use a phone 
patch device plugged into an ATA. The later can handle the simplex 
nature of an FRS/GMRS type radio as it uses a crude noise gate to 
operate the TX. When there is noise (speech/DTMF/whatever) on the line 
side the TX activates otherwise it relays the radio side.

You should also be aware of the legality in your part of the world for 
this type of system. Many PTT's don't allow connection of radio devices 
to the PSTN or Internet either at all or without a waiver.

In the US it is legal on ham bands and GMRS (460MHz) provided the 
operator has "control" and not at all on MURS (156MHz) and FRS (460MHz 
interleaved with GMRS). In the UK its only legal on the ham bands and 
PMR446 as long as the operator is physically present at the RF/Internet 
location. YMMV

Mark, G7LTT/KC2ENI

Shawn Rutledge wrote:
> So has anybody got one of these?  
> 
> http://www.amazon.com/exec/obidos/ASIN/B0007LQQUK/qid%3D1106972010/sr%3D11-1/ref%3Dsr%5F11%5F1/102-1529886-6420131
> 
> I'm thinking that it should be possible to connect it directly to an
> Asterisk box and not use their software, as long as there was Linux
> support for the USB dongle.  Maybe it just looks like a standard USB
> audio device?  But there has to be an extra ring on the connector to
> "key up" the radio so maybe to support that, the usual USB audio
> driver would need some customization.  Just wondering if anybody has
> tried it in Linux.
> 
> If you could do that, then Asterisk could listen for DTMF tones right?
>  So you could use it from any 2-way radio which has a keypad, such as
> a ham 2-meter rig.  (Or hack a keypad into your FRS or CB radio.)  Or,
> Asterisk could be tied to a speech recognition system (like their
> software has) but that is more complex.
> 
> Another aspect is the logic that is required to decide when to
> transmit and when to listen.  You'd need to recognize the presence or
> absence of human voice from both the VOIP end and the radio end, and
> try to balance the two people's rights to monopolize the conversation.
>  The limitation is that the radio is not full-duplex, like a repeater,
> so when the person on the voip end is talking, and the radio whcih is
> attached to the dingotel is transmitting that signal, it is not
> listening, and nothing that the person on the remote radio end says is
> going to get through.  It could be improved by actually using a
> full-duplex radio though.
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-- 

Mark, G7LTT/KC2ENI
Randolph, NJ
http://www.g7ltt.com