[Asterisk-Dev] app_rpt and iaxcomm ptt

[hwstar at rodgers.sdcoxmail.com]

Andreas,

What you are asking for is VOX (voice activated TX). This is not something we wish to support in app_rpt. Detecting audio frames to key and unkey transmitters is not reliable, especially when dealing with stuck transmitters, chopped words and carrier unkey delays.

We use these control frames to ensure the transmitter remains keyed only when it has to be, and also to ensure we never have stuck transmitters if the connection fails. We send the KEY/UNKEY control frames every 5 seconds and the transmitter end has a watchdog timer which looks for them. If the watchdog expires, the transmitter will be unkeyed.


What I would like to know is how difficult it would be to add this functionality to iaxcomm? This is something we want to do for our users, and iaxcomm runs on the 3 major platforms. 

If iaxcomm could be modified to send the control frames periodically that would be great. What we were thinking on doing was to send keying frames when the space bar is pressed, and unkey frames when the space bar is released.
When a connection is configured in iaxcomm, a check box could be set if the end destination is a radio, and then the control frames would be sent for this connection. It would also be nice to configure the caller ID on a per-connection basis as app_rpt uses this to validate the caller.

Steve Rodgers
QRV Communications
http://app-rpt.qrvc.com


 

> 
> From: Andreas Bayer <angel_azrael at gmx.de>
> Date: 2005/08/25 Thu PM 12:48:03 EDT
> To: Asterisk Developers Mailing List <asterisk-dev at lists.digium.com>
> Subject: Re: [Asterisk-Dev] app_rpt and iaxcomm ptt
> 
> Am Donnerstag, 25. August 2005 17:35 schrieb hwstar at rodgers.sdcoxmail.com:
> > We have not tested iaxcomm with app_rpt.
> >
> > app_rpt uses control frames (AST_CONTROL_RADIO_UNKEY,
> > AST_CONTROL_RADIO_KEY) to send key and unkey states. iaxcomm would need to
> > be modified to send these frames when the ptt button is pressed on the
> > client side. It would also be handy to modify iaxcomm to send commands to
> > the radio using text frames.
> 
> i thought iaxcomm (in ptt mode) only send audio frames when the ptt button is 
> pressed.
> 
> It should be easy to implement that app_rpt detect that there a no more audio 
> frames and emulate these control frames.
> There a several voip-clients with functions similar to ptt. So all these apps 
> could be used for radio messages with this emulation.
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