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convertiing a vintge intercom or Dictograph to DTMF

Started by gpo706, June 25, 2012, 11:44:23 AM

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gpo706

Found this on a search, ingenious, but you need 10 buttons or  5 flippers, or 12/6 for your fancy "*/#" functions, the guys done a nice job, look at the labelling on the sets.

http://www.peterbalch.btinternet.co.uk/Phones.htm

"now this should take five minutes, where's me screwdriver went now..?"

twocvbloke

Interesting idea, personally I'd have made up a proper intercom system to go with it than to gut it and make it work on modern phonelines using a modern phone's guts, but, each to their own... :-\

I really hate that term "Steampunk" though (it's on the page title), it's one of them "Look what I made valueless by ripping it apart and throwing in some modern junk to make it work like something modern" things that really winds me up, taking something that could be worth a lot more than they paid, and then pretty much destroying it and it's value just to impress their mates.... ::)

gpo706

#2
I have never heard of that term before 2CV?

If you read through it he says he carefully disassembles the parts and keeps them if needed for re-instatement, personally I quite fancy converting one of my dud 6-key Dictos to DTMF its a really fun conversion, better than sitting in box is it not?

Actually a DTMF Dicto saves flashing the hookset through your Pana PBX, sounds even better now I think about it.
"now this should take five minutes, where's me screwdriver went now..?"

poplar1

What's a skip? ( "I chose to use the electronics from a BT Tribune I found in a skip.")
"C'est pas une restauration, c'est une rénovation."--François Martin.

gpo706

#4
A "dumpster" Poplar, so he actually recycled the guts for the project!

Right - I'm off to look for a NF Tribune...
"now this should take five minutes, where's me screwdriver went now..?"

twocvbloke

Quote from: gpo706 on June 25, 2012, 12:31:33 PM
I have never heard of that term before 2CV?

If you read through it he says he carefully disassembles the parts and keeps them if needed for re-instatement, personally I quite fancy converting one of my dud 6-key Dictos to DTMF its a really fun conversion, better than sitting in box is it not?

Steampunk is a young 'uns term (hate saying that cos I'm only 26 myself!!! :o ), basically a fashion fad, applied to anything vintage they mod into something like that is "steampunked", even if it was not engineered through ages of steam technology, so it's a very nondescript term... ???

I'm sure they are careful to preserve the parts, but others are not, just look on www.instructables.com and search for "steampunk", you'll see what I mean.... :o

gpo706

I take your point, I have looked it up elsewhere, its a very interesting sub-culture, but I agree with you not worth disassembling something with a value to anyone to decorate or embellish some modern tech.

In this case though having looked through his three or four projects he's only taking junk and adapting it to other uses, which are totally reversible in his projects.

There's a Tribune on ebay now which is for spares or not working, is anyone here going to shed a tear if I get a working DTMF Dictograph from its remains?

Maybe some of the worst "steampunk" examples deserve their own thread here?
"now this should take five minutes, where's me screwdriver went now..?"

twocvbloke

I suppose if the owners of such things wish to alter them radically to make them functional, but not obviously so and while making it reversible, then I suppose there's not much loss, I wouldn't but that's just me...  ;D

We used to have a Tribune years ago, LD-only and had a proper bell in it, and in the house we were in at the time being made of paper walls and matchstick floors (very cheap 1980's construction, wouldn't pass building inspections today!!), it could be heard ringing throughout the house, haven't a clue what happened to that phone, but I'm not that bothered about getting another, I prefer the Viscounts from the same era... :D

Owain

if you want to be really steampunky you'd have 7 separate switches for the rows and columns, and operate two simultaneously to get the dual-tone.

gpo706

Indeed Owain!

Here's a reply from the man himself he sent today;

Hello Scot

I'm glad you like the conversion. Everyone who comes to the house comments
on it.

I've recently done a couple more old phones - a pushbutton one and a rotary
dial 1920 candlestick telephone. I'll put photos on the website soon.

> I have a few Dictographs that work as one key flipped dial tone units,

What are they like? Are there any photos on the web?

> can you advise me how to convert a 6-key set for DTMF if I find a
> suitable PCB?

Are you in the UK or US? That will determine what kind of modern phone you
should start with.

My Dictograph was an easy conversion because the box is so large. Pretty
well any phone electronics will fit. Phones cost around £1 in car-boot
sales. Alternatively, brand new ones can be found for under £10. - for
instance, this has 10 memories
http://www.argos.co.uk/static/Product/partNumber/5521618/Trail/searchtext%3ETELEPHONE.htm#pdpFullProductInformation

I chose the Tribune as it was the only one I had with a bell rather than a
beeper but, on reflection, that was probably a mistake. All the other
conversions I've done have use phones with a memory and it's a bit annoying
that the Dictograph doesn't.

I used the 6 keys up/down (i.e. 12 switches) as 0..9 * #.

I would do it now as 0..9 STORE and QUICKDIAL. But then what if you needed #
and * for the automated call centre style "press # for more options"? I
guess I'd use a different phone.

Internally, the Dictograph 12 positions are 12 individual switches so,
again, it's an easy conversion. The pcb of any modern phone will look
something like this
http://www.datamath.org/BASIC/LCD_Classic/JPEG_TI-1750.htm
(OK, that's a calculator but it's the same).

Note how each key has pcb track "fingers" under it. You just replace each
key with a Dictograph switch by connecting wires from the switch to the two
sides of the "fingers".

Take your modern phone apart and touch a short length of wire to connect
across the "fingers" - you'll hear the phone producing the DTMF codes.

You can save some wiring by tracing the tracks on the pcb. You'll find that
the keys are arranged in a matrix like this:
http://www.dnatechindia.com/Tutorial/8051-Tutorial/Interfacing-Matrix-Keypad-to-8051.html
(but usually not in quite such an orderly fashion). So you can solder fewer
wires to the pcb.

> I would need some advise on how to remove the flipper lock internals,
> obviously.

IIRC, it was easy. The back of each flipper is an arc of metal with 3
notches in it (for up, middle and down). A sprung bar fitted into the
notches and held all the flippers in place. If any switch was moved, it
raised the bar and released any switch that was being held.

I just removed the bar.

For the Dictograph, I replaced both the microphone and speaker. But, in
fact, most of the speakers in old phones work fine with modern electronics.

A good trick for making modern cables look old is to feed them through a
large brown bootlace.

Good luck

Peter
"now this should take five minutes, where's me screwdriver went now..?"