Use your vintage pulse dial telephone on Skype
Posted by g7fek on Sun, 10 May 2009 22:19:18 +0100

A VoIP adaptor and vintage telephone line simulator for Skype. Both Practical and Fun!!.

I have built and installed this novel Skype device on my home computer. It simulates a telephone line so that you can plug an ordinary telephone into the unit. The big difference between this unit and other Skype Boxes is that it uses the vintage pulse dial (loop disconnect) instead of DTMF, and that you can build it yourself. This makes it unique in that it will allow you to dial out on Skype using a vintage telephone with a rotary dialler.

I have mine set up using my old GPO type 706 telephone which was made in 1970. I am amazed at how well this works. The bell rings as soon as someone calls my skype number and i can dial anyone using the rotary dial. But the best part is that I can assign short numbers to people I call regularly, it would be too much to dial an eleven digit number for every call, so I have allocated 4 digit numbers for my friends.

Easy to Build

Although you can get this ready built, I built it myself. It was actually quite easy because the unit has been cleverly designed to make maximum use of the PC and keep the hardware really simple. There are no IC's, just three transistors and several passives on a single sided PCB. The whole lot is assembled into a neat modern case.

Speaking Clock.

I love the speaking clock feature. I have it on 8081 just like when I was a lad and my mom would tell me off for phoning the very expensive speaking clock. Although the voice is not the original, the simulation is very accurate and I used the supplied program to synchronise it with the atomic clock.

Vintage or Modern

The unit comes with two different dial tones. One is the standard modern one we are all familiar with, and the other is the old 33Hz buzz that our UK phones had in the 60's and 70's. It sounds very authentic and the experience is very realistic.


In summary I would say this is a great little unit. It is both a practical VoIP adaptor and a bit of vintage nostalgia at the same time. Also if you are looking for a home-brew project it's easy to build and has a very practical use. On the downside it uses the PC Parallel Port and not USB, so people with modern laptops may not be able to use it. All my computers at home have a parallel port connector, including my laptop, so it was not a problem for me. You can buy PCI parallel ports from the website if your computer doesn't have one, but still no good for laptops. There is a special USB upgraded planned.

The reason behind the choice of port was both to save costs on the extra hardware and software needed for USB and at the same time, keep the unit easy to build by eliminating the need for any IC's, especially surface mount, which would have made home construction impossible for some of us.

You can find out more here at

Comment by 'Mike, G7FEK' on 26 Apr 2013 - comment
“Hi Martin. I have sent you a detailed email about this. It may be possible to bring this product back as an Open Source project. I am looking into it.”

Comment by 'Martin Palmer' on 17 Apr 2013 - comment
“Hi, I really want one of these units but all I get from the contact/information form on is an automated reply and a promise of more information at a later date. Do you know if this site is still operating or if there's any other way to contact them? Many thanks.”

Comment by 'admin' on 10 Apr 2010 - comment
“Due to the hideousness of Skype 4, I will not be making a Skype 4 version of this product. Unfortunately Skype users are restricted to just one software product and when it goes bad, as Skype has done with version 4, you are stuck. So SP version 1 will remain for Skype 3.8 only. SP version 2 will be using the open standard SIP protocol and connect to serial or USB ports. Versions for Windows, Linux and Mac should now be possible.”

Comment by 'Mike G7FEK' on 24 Nov 2009 - comment
“The USB version will soon be available. The firmware is ready, the PC client is not yet finished. Use your Pulse Dialling Telephone on Skype. ”