<html><head/><body><html><head><meta content="text/html; charset=ISO-8859-1" http-equiv="Content-Type" /><meta content="text/html; charset=ISO-8859-1" http-equiv="Content-Type" /></head><body bgcolor="#FFFFFF" text="#000000">Two tone voice pagers are still the defacto standard for volunteer fire departments in this part of the world, so it isn't so obsolete. Some areas each department has their own radio frequency, and tones for the pagers may or may not overlap, other areas use a shared frequency for the county, with different departments having different tone pairs. The county to the North of me, when they do their weekly test, sends tones for almost 2 minutes before the dispatcher can put out the announcement. (4 seconds per pair, 50 something paging groups)<br><br><div class="gmail_quote">Tony Langdon <vk3jed@vkradio.com> wrote:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div class="moz-cite-prefix">On 27/05/13 3:34 AM, Bear Albrecht
wrote:<br />
</div>
<blockquote cite="mid:51A247B7.8000702@gmail.com" type="cite">
<div class="moz-cite-prefix">On 5/26/13 11:10 AM, Brad NK8J wrote:<br />
</div>
<blockquote cite="mid:001801ce5a33$f1fc7890$d5f569b0$@juno.com" type="cite">
<pre wrap="">Most Fire Stations and ambulances require DTMF Tones to tell them which
station is being sent out to where. </pre>
</blockquote>
Well, not exactly. The system here is "two-tone" which has one
single tone transmitted for a couple of seconds and then another
single tone for a couple of seconds. Precise timing I can look up
on Tuesday if needed. Google "two tone paging" for some of the
angles. <a moz-do-not-send="true" class="moz-txt-link-freetext" href="http://www.batlabs.com/qcii.html">http://www.batlabs.com/qcii.html</a>
has some of the info although it doesn't cover what we use, nor
several other variants.<br />
</blockquote>
We used to use that here in the late 1980s. I was toying with the
idea of building a decoder (before software methods were practical)
when we had the system installed. I got good at picking the tones
by ear in the end, could tell ours from others in use. Those days
are long gone, as we now use a statewide single frequency POCSAG
network, independent of the voice channels for emergency callouts.<br />
<br />
<pre class="moz-signature" cols="72">--
73 de Tony VK3JED
<a class="moz-txt-link-freetext" href="http://vkradio.com">http://vkradio.com</a></pre>
<p style="margin-top: 2.5em; margin-bottom: 1em; border-bottom: 1px solid #000"></p><pre style="white-space: pre-wrap; word-wrap:break-word; font-family: sans-serif; margin-top: 0px"><hr /><br />chirp_users mailing list<br />chirp_users@intrepid.danplanet.com<br /><a href="http://intrepid.danplanet.com/mailman/listinfo/chirp_users">http://intrepid.danplanet.com/mailman/listinfo/chirp_users</a><br /></pre></blockquote></div><br>
-- <br>
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