Re-installing a TouchTone keypad in an ASR-33

dwight elvey dkelvey at
Wed May 20 20:27:51 CDT 2009

> Date: Wed, 20 May 2009 15:56:07 -0400
> Subject: Re: Re-installing a TouchTone keypad in an ASR-33
> From: ethan.dicks at
> I couldn't say for certain, but even into the 1990s, the phone company
> charged $1-$2USD/month for TouchTone service. Mostly by then, it was
> just a surcharge applied to your bill for their convenience. When I
> got a data line for UUCP around 1990 or so, I told them "no extras" -
> no call-waiting, no three-way-calling, no speed-dial, and no
> TouchTone. They tried to persuade me to get their profit-laden
> features, but they really balked at setting me up a pulse-dial line.
> I suggested that if it wasn't an option that could be canceled, then
> perhaps they were exceeding the rates set by agreement with the Public
> Utilities Commission. They acquiesced. I did have to patch the UUCP
> dialer program (I was calling from an Amiga and didn't have the right
> compiler environment to build from source) because you could _not_
> pick pulse dial from L.sys because the app had "ATDT" hard-coded. A
> quick change to ATDP and it was happy.
The last time I had a connection, I told them I didn't
want the touch-tone feature ( a few dollars a month ).
I don't pay for it but I've used a touch-tone phone on
my line several times. I suspect that like you, it was
too much trouble to remove so they just left it connected.

> If it's an ITT or other non-Western Electric phone, I'd wager it's
> IC-based. AFAIK, only the W-E phones (i.e., pre-breakup) would have
> the 1-transistor-2-coil keypad.
> -ethan
 I used to work for a company call SpeedCall. They made
touch tone decoders for taxi cabs and similar uses.
They all decoded with coil and capacitor. Only the coil had to
be exactly wound ( to the turn ). It had a slug to tune
it to work with the capacitor used with it.

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