Order Tray | Contact Us | Home | SIG Lists

[aprssig] An amusing aside (Text Pagers)

Alex Carver kf4lvz at yahoo.com
Sat Jan 30 18:07:20 UTC 2010

> From: "Wes Johnston, AI4PX" 
> Subject: Re: [aprssig] An amusing aside (Text Pagers)

> If we had a way to see the numbers we've entered, or
> somehow compose a
> message / posit packet offline, then have a pic processor
> spit out the DTMF
> string for us, we'd have a winner.  But then again,
> why not have the little
> pic processor spit out a normal packet?  the answer
> may be that a 1200 baud
> AFSK packet can't be squirted in by holding a small device
> close to a
> microphone... the DTMF's can. So I could use this little
> cigarette sized
> black box with an lcd display on it to compose a position
> report "off
> line",then it would build the DTMF tones needed to convey
> my info.  I would
> hold this near the mic of any radio or HT and vollia. 
> This would be the
> deal maker.  Preprogramming DTMFs in one or two
> memories is close, but no
> cigar.  Along the same lines, we *could* compose aprs
> packets by hand, but
> we all use software to build the packets for us.  This
> should be no
> different.  The true "hacker"/ "uber geek" types can
> certainly punch all the
> right DTMF sequence, but to reach the masses, a helper
> device would go a
> long way toward general acceptance / useage.

What you just described is identical to the old pocket dialers that used to be sold in places like Radio Shack during the 80's and up to the early 90's prior to the true rollout of cellular service when payphones reigned.  It was a little pocket box with a keypad on it and enough memory for 100 ten digit phone numbers.  A person would hold the dialer up to the handset of the payphone (after inserting correct change) and then recall one of the stored memory slots.  It would warble out the DTMF tones right into the microphone and dial the payphone.  Some of the later versions had LCD screens on them so you could see what was typed.

I've seen this written as software for PDAs now, but you can probably still find the hardware versions laying around on eBay or other places.  I found a couple just with a quick search for "Pocket tone dialer":

http://cgi.ebay.com/Sharp-EL-6250-Dial-Master-Pocket-Calculator-Dialer_W0QQitemZ120524337611QQcmdZViewItemQQptZCalculators?hash=item1c0fcf71cb (wrapped link)


More information about the aprssig mailing list