The Retrophone telephone exchange

On this site you will find my own version of the 'Wonderfoon'. I have already taken care of many beautiful classic telephones, but it is time for reflection. It gnawed at my craft heart to have to demolish such a beautiful piece of vintage technology to make the necessary adjustments.

That is why it is time for a new design: the Retrophone telephone exchange switchboard!

This is a box that can be supplied in various versions. Any classic or modern telephone can be connected to it. The basic model is 'open-source'. The schematic, the software, the design of the printed circuit board and the 3D design of the box can be used by anyone with some technical knowledge to build one themselves. This switchboard can be used with dial telephones as well as with the more modern push-button (DTMF, such as the T65 TDK) telephones.

Just plug in your phone and you're done. Hundreds of different music or audio fragments can be played with it. The phone actually waits for the dialing of a complete phone number and bases on which fragment is played. Because the configuration process can only be started by pressing a key on the switchboard case itself (not by dialing a 'special' telephone number), unintentional misconfiguration in the (semi-)public space is excluded.

Not long after the Retrophone Nostalgia will become available, it will be possible to build various professional variants of this telephone switchboard to order. As with the basic model, indicator lights on the housing provide feedback on the use of the phone (hook off, dialing process, audio playing, etc), but this Retrophone Professional has a number of attractive additional options:

  • The bell of any connected telephone can ring on command. This means that the phone can also be used as an alarm clock or timer. After the elapsed time, a (configurable) audio fragment is played.
  • When 'calling' 002 (or the present 0900-8002) the actual time is spoken by a friendly voice. In this hectic world where every microwave already has a clock, you can keep up to date in a fun and historically responsible way.
  • Configurable inputs allow the phone to react to its environment. For example, the phone can start ringing after a signal from a proximity sensor and play a certain audio fragment as soon as the handset is lifted.
  • This switchboard has configurable switching (230 volts, if necessary) outputs. With this, for example, a door can be opened in an escape room after dialing a certain telephone number.

The possibilities of the Retrophone Professional are completely adapted to your wishes. Tailor-made software and audio make this telephone exchange module unique. Because the specific software and functionality are customized, it is the ideal piece of hardware for stage performances, film recordings, museums, exhibitions and Escape Rooms.

In development...

The schematic of this basic 'Wonderfoon', the Retrophone Nostalgia, has now been drawn and the electronics have been thoroughly tested. I am currently waiting for the first series of printed circuit boards. I will use the intervening time to further document the project, write a manual and building instructions, make a video and bring the stock of parts up to standard so that I can soon start building and offering the first series of ready-made cabinets. Keep an eye on this site for that!


Work in progress...

Despite the somewhat messy spring period with the necessary chores around the house, developments have not quite stood still in the meantime. On the contrary actually. The first prints have been assembled and some refinements (and simplifications) have been made to the schematics. The housing has been designed and the first 'wall boxes' have been realised. Naturally, the well-known vintage PTT colors have not been forgotten for the real enthusiasts!

Retrophone - Various Colours Retrophone - Prototype White Retrophone - Various Colours 2

The various sub-principles have been tested in software, but the 'real' complete operating system still needs to be developed further. It is expected that this can be completed after the summer holidays. A slightly 'delaying' factor is the extensive documentation and making videos for my YouTube channel. The first movie is about detecting and the 'digital preprocessing' of the various telephone signals (hook, dial pulses, DTMF tone decoder, etc.). There are also plans for a separate video about techniques to ring the bell of the telephone. However, this initially falls outside the scope of the basic Retrophone, which accommodates the functionality of the well-known 'Wonderfoon' in a switchboard and, if necessary, expands it with the possibility to also use push-button telephones. A movie about a modular Retrophone (with optional 'ringing', a clock and optional input and output options) concludes the intended series.

The technique, schematics, 3D case design, PCB designs and software of the Retrophone switchboard will be open source for non-commercial purposes. This means that any (advanced) technician may reproduce them for non-commercial purposes. Advertising with it online and building it to order against payment is reserved for me for the time being. The technology behind the upcoming modular Retrophone can easily be learned from the movies and documenting web pages. It is difficult to give a ready-made construction design because this power station can be built by me to order with specific requirements such as customization.

Keep me posted...

If you would like to be notified when the Retrophone is available, please leave your email address using the form below. I promise that I will not send newsletters and other spam.

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