AH!  Besides answering another question I had about the "audio standard" on Asterisk being "line level" spkr/mic audio, you are sying the txprelim=yes is not what does it in a RTCM?  Does that still need to be set?
 
Sounds like  you are basically "fooling" it by telling it to generate a PL, which makes it think it is connected directly to a modulator, hence it will pre-emphasize the audio automatically? Setting the txctcsslevel=0 just kills the tone.
 
Do I have it correct now?
 
ALSO,
  Since chan_simpleusb will not pre-emph, will a DMK URI do it if you use the chan_usbradio to drive it?
 
Lets see how many other questions I can cram in here.....
 
  I assume since I do not have an RTCM yet, that the chan_voter is what is used for the RTCM?  Even if it is NOT being used as a voter system, just a radio interface?
 
Thakns for the help Tim!!
 
I'm learnin'
 
73 de Greg
----- Original Message -----
From: Tim Sawyer
To: KJ6KO
Cc: App_rpt-users@ohnosec.org
Sent: Wednesday, August 28, 2013 12:46 PM
Subject: Re: [App_rpt-users] RTCM txprelim?

Sorry, this deserves a better expansion. Sometimes I get in a hurry.

Asterisk ships audio around (on the links, etc) as line-level audio (not pre-emphasized and needs no de-epmhasis). This works out great for telephones, computer clients, voice announcements, etc because Asterisk doesn't have to do any filtering. After all Asterisk is a telephone PBX where you would expect audio to be line-level (speaker/mic) audio. This leaves the pre/de-emphasis up to app_rpt channel drivers. Chan_usbradio and chan_voter can add pre-emphasis. Chan_simpleusb cannot pre-emphasise. 

With chan_voter the DSP pre-emphasis is turned on by setting txctcss = xxx.x in voter.conf. If you want pre-emphasis but no TX P/L set txctcss =  to some (any) tone and set txctcsslevel = 0.

Hope that helps.
--
Tim
:wq

On Aug 28, 2013, at 10:26 AM, Tim Sawyer <tim.sawyer@me.com> wrote:

Absolutely, yes. That is it's normal mode. 
--
Tim
:wq

On Aug 28, 2013, at 9:42 AM, KJ6KO <kj6ko@innercite.com> wrote:

I am looking into an RTCM.  Does it have the capability of driving a modulator directly?  May have to use it with an old Palomar controller which is set up for direct modulator input style TX audio (pre-emphasized)
 
txprelim=yes?
 
I know it has the ability to de-emphasize the DISC audio from the Palomar.
 
Thanks..


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