<div dir="ltr"><div>I don't think is does. That is why when you radio loses sync you get R2D2 and others remain able to receive. If I read the protocol documents correctly it is all fire and forget much like the VOIP protocols mentioned before.</div>
</div><div class="gmail_extra"><br><br><div class="gmail_quote">On Fri, Sep 20, 2013 at 6:23 PM, Joel Black <span dir="ltr"><<a href="mailto:w4jbb@charter.net" target="_blank">w4jbb@charter.net</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
Okay, this goes against what little I have learned about VoIP
traffic.<br>
<br>
I didn't think there was any FEC with voice. That's why voice has
priority on data networks that use VoIP. Otherwise, if a data
packet has priority, it would bump a voice packet. When a voice
packet is bumped, you lose bits of it resulting in choppy audio.<br>
<br>
I have experienced this when some of our first quasi VoIP locations
came online. Voice is live traffic. Once it is said, it goes.
There's nothing to re-transmit.<br>
<br>
Without getting into the engineering (which will leave me drooling
and nodding off to sleep), how does D-STAR use FEC on voice?<br>
<br>
73,<br>
Joel - W4JBB<div><div class="h5"><br>
<br>
<div>On 9/20/13 3:57 PM, John Davis wrote:<br>
</div>
<blockquote type="cite">
<div>
<p class="MsoNormal"><span style="color:rgb(31,73,125);font-family:"Calibri","sans-serif";font-size:11pt">That
is true. The FEC is on the voice with 2400 bits for voice
and 1200 for FEC.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="color:rgb(31,73,125);font-family:"Calibri","sans-serif";font-size:11pt"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="color:rgb(31,73,125);font-family:"Calibri","sans-serif";font-size:11pt">John
WB4QDX<u></u><u></u></span></p>
<p class="MsoNormal"><span style="color:rgb(31,73,125);font-family:"Calibri","sans-serif";font-size:11pt"><u></u> <u></u></span></p>
<p class="MsoNormal"><b><span style="font-family:"Calibri","sans-serif";font-size:11pt">From:</span></b><span style="font-family:"Calibri","sans-serif";font-size:11pt">
<a href="mailto:drats_users-bounces@intrepid.danplanet.com" target="_blank">drats_users-bounces@intrepid.danplanet.com</a>
[<a href="mailto:drats_users-bounces@intrepid.danplanet.com" target="_blank">mailto:drats_users-bounces@intrepid.danplanet.com</a>]
<b>On Behalf Of </b>Daniel Metcalf<br>
<b>Sent:</b> Friday, September 20, 2013 4:55 PM<br>
<b>To:</b> Discussion of D-RATS<br>
<b>Subject:</b> Re: [drats_users] ERROR Correction in slow
speed data<u></u><u></u></span></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p>Agreed. From what I have read d-star is a lot like the UDP
network protocol where it is transmit and forget there is no
handshaking / error correction built in. It is up to the
application developer to handle error correction and the
d-rats package does perform some level of error correction.<u></u><u></u></p>
<p>Dan Metcalf - KB3UUN.<u></u><u></u></p>
<div>
<p class="MsoNormal">On Sep 20, 2013 3:54 PM, "John Davis"
<<a href="mailto:jdavis@gtworks.com" target="_blank">jdavis@gtworks.com</a>>
wrote:<u></u><u></u></p>
<blockquote style="border-width:medium medium medium 1pt;border-style:none none none solid;border-color:currentColor currentColor currentColor rgb(204,204,204);padding:0in 0in 0in 6pt;margin-right:0in;margin-left:4.8pt">
<div>
<div>
<p class="MsoNormal"><span style="color:rgb(31,73,125);font-family:"Calibri","sans-serif";font-size:11pt">My
understanding is that the low speed data channel
does NOT have error correction, however, D-RATS
offers Error correction in Message and File Transfer
modes where it is most important.</span><u></u><u></u></p>
<p class="MsoNormal"><span style="color:rgb(31,73,125);font-family:"Calibri","sans-serif";font-size:11pt"> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="color:rgb(31,73,125);font-family:"Calibri","sans-serif";font-size:11pt">John
WB4QDX</span><u></u><u></u></p>
<p class="MsoNormal"><span style="color:rgb(31,73,125);font-family:"Calibri","sans-serif";font-size:11pt"> </span><u></u><u></u></p>
<div>
<div style="border-width:1pt medium medium;border-style:solid none none;border-color:rgb(225,225,225) currentColor currentColor;padding:3pt 0in 0in">
<p class="MsoNormal"><b><span style="font-family:"Calibri","sans-serif";font-size:11pt">From:</span></b><span style="font-family:"Calibri","sans-serif";font-size:11pt">
<a href="mailto:drats_users-bounces@intrepid.danplanet.com" target="_blank">drats_users-bounces@intrepid.danplanet.com</a>
[mailto:<a href="mailto:drats_users-bounces@intrepid.danplanet.com" target="_blank">drats_users-bounces@intrepid.danplanet.com</a>]
<b>On Behalf Of </b>Dave Welker<br>
<b>Sent:</b> Friday, September 20, 2013 3:19 PM<br>
<b>To:</b> D-Rats Mailing List<br>
<b>Subject:</b> [drats_users] ERROR Correction
in slow speed data</span><u></u><u></u></p>
</div>
</div>
<p class="MsoNormal"> <u></u><u></u></p>
<div>
<p class="MsoNormal"><span>Hello all,</span><u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><span>Can anyone
confirm if the D-RATS slow speed data has FEC
(Forward Error Correction) built in now or not?</span><u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><span>I understand
that D-STAR voice does have error correction built
in. I've checked on the D-RATS home
page/documentation</span><u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><span>which is a
August 2009 reference.</span><u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><span>This is what
I found in this document Under users
manual/files: Is this still current information?</span><u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p style="background:white;margin:0in 0in 0pt;word-spacing:0px"><strong><span style="color:rgb(102,102,102);font-family:"Verdana","sans-serif"">Unlike
the D-STAR DV Voice Channel, which has error
correction built into the protocol, the Data
Sub-channel has no error correction. </span></strong><u></u><u></u></p>
<p style="background:white;margin:0in 0in 0pt;line-height:11.25pt;word-spacing:0px"><span style="color:rgb(102,102,102);font-family:"Verdana","sans-serif";font-size:9pt"> </span><u></u><u></u></p>
<p style="background:white;margin:0in 0in 0pt;word-spacing:0px"><strong><span style="color:rgb(102,102,102);font-family:"Verdana","sans-serif"">This
makes the transfer of data across D-STAR a lot
more dependant on a good radio path being
established between the two locations wishing to
</span></strong><u></u><u></u></p>
<p style="background:white;margin:0in 0in 0pt;line-height:11.25pt;word-spacing:0px"><span style="color:rgb(102,102,102);font-family:"Verdana","sans-serif";font-size:9pt"> </span><u></u><u></u></p>
<p style="background:white;margin:0in 0in 0pt;word-spacing:0px"><strong><span style="color:rgb(102,102,102);font-family:"Verdana","sans-serif"">exchange
data. D-RATS includes the ability to test
connectivity between two locations</span></strong><strong><span style="color:rgb(102,102,102);font-family:"Verdana","sans-serif";font-size:9pt">.</span></strong><u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><span>Thanks in
advance</span><u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><span>regards</span><u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><span>Dave</span><u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><span>W2SRP</span><u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><span>Goals are
where we want to be;<br>
Objectives are the steps to get there.</span><u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><span>There are 2
rules to success in life:<br>
1. Don't tell people everything you know.</span><u></u><u></u></p>
</div>
</div>
</div>
<p class="MsoNormal" style="margin-bottom:12pt"><br>
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</blockquote>
</div>
</div>
<br>
<fieldset></fieldset>
<br>
<pre>_______________________________________________
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</blockquote>
<br>
</div></div></div>
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<br></blockquote></div><br><br clear="all"><br>-- <br><div>Dan Metcalf -- KB3UUN</div><div>c. 301 769 1111</div><div> </div><div>Amateur Radio has something for everyone. Even if it is just peace of mind that no matter what happens your message will get through.</div>
</div>