[App_rpt-users] DMK URI questions

Sat Nov 2 17:55:24 UTC 2013

Perhaps some useful information.

http://www.carolina440.net/flataudio_.pdf

Regards,
Doug - GM7SVK

----- Original Message ----- 
From: "Doug Crompton" <doug at crompton.com>
To: "Tim Sawyer" <tim.sawyer at mac.com>
Cc: <app_rpt-users at ohnosec.org>
Sent: Saturday, November 02, 2013 4:53 PM
Subject: Re: [App_rpt-users] DMK URI questions

OK the two differing opinion responses explain the difference.

If I decide to start with simple USB and CTSS decoding in my transceiver fed 
to the URI cos pin would I use flat audio or dempahsized audio from the 
transceiver?  In the case of the Alinco either the 1200 baud or 9600 baud 
audio data port outputs?  And what input to the Alinco for TX (1200 or 
9600)?

This is confusing because I am not sure if a setting of simple USB also 
means you send demphasized audio to the interface or do you always send 
"flat" audio to the interface. And the same question for audio from the 
interface to the TX.

I am assuming the term "flat" means before any pre/demphasis.
73 Doug
WA3DSP
http://www.crompton.com/hamradio

Subject: Re: [App_rpt-users]  DMK URI questions
From: tim.sawyer at mac.com
Date: Sat, 2 Nov 2013 08:56:01 -0700
CC: app_rpt-users at ohnosec.org
To: doug at crompton.com

The DMK URI works with either SimpleUSB or USBradio (DSP).
- Both USBradio and SimpleUSB can do CTCSS high pass filtering and 
de-emphasis.- SimpleUSB cannot do noise squelch, CTCSS squelch or 
pre-emphasis.- SimpleUSB requires less CPU.
You may not desire or be able to use USBradio:- If you have a low speed 
(less than 800 Mhz) CPU- If you can’t get discriminator audio out of your 
radio- If your radio does not produce enough high frequency discriminator 
audio- If you find the squelch action of your radio better than that of 
USBradio
Personally I prefer SimpleUSB over USBradio. I use with commercial Motorola 
repeaters on congested hill tops. The squelch and CTCSS decode are miles 
better than USBradio in my opinion.
Tim:wq

On Nov 2, 2013, at 7:41 AM, Doug Crompton <doug at crompton.com> wrote:OK 
Perhaps I am not using the right Allstar terminology here.  My understanding 
is that simple USB works similar to IRLP in that you use pre/dempahsized 
audio and COS and there is no further processing. CTSS tones, squelch, etc. 
are not decoded by the SW but rather by the incoming DC level of COS.

On the other hand in what I call DSP the CTSS, etc. are decoded by the 
software. As a for instance the GM300 example on the DMK site uses no COS 
just audio in, out, and PTT. When using this mode you use flat audio from 
the RX or audio that has not been demphasized.

DSP is digital signal processing.  That is what the SW does to look at the 
incoming signal to decode things like CTSS, DTMF, squelch noise etc.  I am 
assuming that simple USB just uses the COS signal to detect carrier. My 
question was why would one prefer one method over the other or does one work 
better than the other.
73 Doug
WA3DSP
http://www.crompton.com/hamradio

From: kj6ko at innercite.com
To: doug at crompton.com
Subject: Re: [App_rpt-users] DMK URI questions
Date: Sat, 2 Nov 2013 00:13:15 -0700

Doesn't matter.  It's a preference thing.  By the time audio gets to the 
internet, it is all digitized and de-emphasized.  What comes out the other 
end depends on what you want.  If you are going to feed a modulator 
directly, you need pre-emphasized audio, and I don't think the URI will do 
that.  It will de-emphasize DISC audio on RX.  You should just use MIC audio 
into the radio and de-emphasized audio into the URI to keep it simple.  I 
would ALWAYS use "CTCSS Valid" signal out of the radio (if avail) and feed 
the signal to the COS port of the URI. COS and CTCSS are meant to be used 
together, like in a repeater, but it doesn't have to be MIC DC and MIC AC?? 
you will have to read the radio manual on that one. PS:  DSP does NOT mean 
FLAT Audio.  It means "Digital Signal Processing" and really has nothing to 
do with audio shape. I guess I'm not sure what you mean by "DSP vs Simple 
USB"??  Is there a device called a "DSP?"  I'm guessing you should keep it 
simple and use the "Simple USB" because that is what it is...simple!  Not 
much involved, Audio in, audio out, PTT Out and COR/CTCSS in.(Either or). 
For a CTCSS detect, you need to find something that will give a GND or +5VDC 
when an active PL Tone is received.  I think the DMK device can do this for 
you if you don't have one on your radio, in which case you will HAVE to use 
discriminator audio for RX.  The DMK will de-emphasize it before it goes out 
over the network. ----- Original Message -----From: Doug CromptonTo: 
app_rpt-users at ohnosec.orgSent: Friday, November 01, 2013 10:53 PMSubject: 
[App_rpt-users] DMK URI questions
About a week ago I asked about DMK URI connections to an Alinco radio and I 
got several responses. I do have a few more questions regarding that.

The Alinco has both flat and pre/de-emphasized audio available on its data 
connector as 1200 baud and 9600 baud connections.

I assume I would use the 1200 baud connections along with COS and PTT for a 
simple USB interface and the 9600 baud connections along with just the PTT 
for a DSP interface?

Do I use the  (Alinco 9600 baud) audio to the TX also? Does the DSP 
pre-emphasize audio or is the processing just on the receive side?

Why would I want to use one over the other (DSP vs simple USB)? Which is 
preferred and/or works better? I am thinking there might be some differing 
opinions here!

The DMK URI has both mic_DC and mic_AC inputs. Does this refer to frequency 
response or just that one has DC blocking?

If you are using flat response (DSP) would the audio in (from the receiver) 
connections at the URI end matter?

The DMK URI has both COS and CTSS inputs. Why would you use one over the 
other? When using DSP I assume neither is needed?

All of the questions above assume I am using the Acid release on a faster 
processor.

73 Doug
WA3DSP
http://www.crompton.com/hamradio

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