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</head><body text="#000000">The analog in-band tone signaling system was
developed way back in the late 1930s, when the equipment needed to
generate, and receive, the signaling tones was all vacuum-tube based and
found only in telephone central offices. (Not only was there the 2600Hz
on-hook/off-hook supervision signaling, but also the two-out-of-five
code multi-frequency—MF—signaling of called numbers.) <br>
<br>
Tone signaling systems were deployed with long-distance ("toll")
switching systems, starting (IIRC) just before WW II. "Long Distance"
operator consoles had keypads enabling operators to signal the distant
phone number you wanted (obviously way before Direct Distance Dialing in
the late '50s).<br>
<br>
Once it became really easy to build battery-powered transistorized
circuitry to generate the requisite tones, the whole system became
vulnerable to hacking in the '60s and '70s.<br>
<br>
Ken Pogran<br>
<br>
<span>Steve Isenberg via LCTG wrote on 4/9/25 11:35 PM:</span><br>
<blockquote type="cite"
cite="mid:CAL0r4CCUaTuzqZpYRg=S5GXPWufvNTQLFscdv+zQnfmAeZTfrQ@mail.gmail.com">
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<div dir="auto">I found that I could call an 800 number, whistle the
frequency, and hear the tandem drop; I didn’t need the Captain crunch
whistle.</div>
<div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr"
class="gmail_attr">On Wed, Apr 9, 2025 at 10:29 AM Adam Broun via LCTG
<<a href="mailto:lctg@lists.toku.us" moz-do-not-send="true">lctg@lists.toku.us</a>>
wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px
0px
0.8ex;border-left-width:1px;border-left-style:solid;padding-left:1ex;border-left-color:rgb(204,204,204)"><div
dir="ltr"><div dir="ltr">Did anyone here ever use the infamous Cap'n
Crunch whistle?</div><br></div><div dir="ltr"><div class="gmail_quote"><div
dir="ltr" class="gmail_attr">On Wed, Apr 9, 2025 at 10:23 AM Donald
Cooke via LCTG <<a href="mailto:lctg@lists.toku.us" target="_blank"
moz-do-not-send="true">lctg@lists.toku.us</a>> wrote:<br></div></div></div><div
dir="ltr"><div class="gmail_quote"><blockquote class="gmail_quote"
style="margin:0px 0px 0px
0.8ex;border-left-width:1px;border-left-style:solid;padding-left:1ex;border-left-color:rgb(204,204,204)"><div
dir="ltr"><div>They came around to Hancock School to teach us kids.
Must have been my 5th grade or so. Our number changed from
Lexington-9-0524 to Volunteer-2-5010. I think we also got to walk down
to the switch station on Waltham Street to see the switching mechanism. </div><div><br></div><div>Later
on I learned that I could dial a number by just pressing the hangup
switch rapidly.....</div><div><div dir="ltr" class="gmail_signature"><div
dir="ltr"><div><br></div>Don Cooke, Site 523, 603.219.9259<br>
</div></div></div><br></div><br><div class="gmail_quote"><div dir="ltr"
class="gmail_attr">On Wed, Apr 9, 2025 at 5:43 AM John Rudy via LCTG
<<a href="mailto:lctg@lists.toku.us" target="_blank"
moz-do-not-send="true">lctg@lists.toku.us</a>> wrote:<br></div><blockquote
class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left-width:1px;border-left-style:solid;padding-left:1ex;border-left-color:rgb(204,204,204)"><div><div
lang="EN-US"><div><p class="MsoNormal"><a
href="https://www.bing.com/videos/riverview/relatedvideo?q=how+to+use+a+dial+phone+1954&mid=7F1DA87AF463381268157F1DA87AF46338126815&FORM=VIRE"
target="_blank" moz-do-not-send="true">Bing Videos</a></p><p
class="MsoNormal">This is pretty amazing</p><p class="MsoNormal"> </p><p
class="MsoNormal"><span
style="font-size:10pt;font-family:Arial,sans-serif">John Rudy</span><br>
</p></div></div></div></blockquote></div></blockquote></div></div></blockquote></div></div>
</blockquote>
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