The first idea was to attach the handset to my Android phone and use it there.
To find out what quality is possible with such a headset I bought a Nokia handsfree.
Than I started some experiments.
Step 1: The Headset
Then I replaced the original earphone of the handsfree set by the speaker inside the vintage handset.
The sound was loud and clear. :-)
The keyboard of the Nokia mobile was a bit damaged. So I changed my mind and decided to build a new keyboard by my own.
Step 2: The Keyboard
Than I polished the small contacts there are located under the keyboard an soldered two wires on each pair of contacts.
From the Internet I bought a couple of push buttons.
I redesign the keys on my computer and printed it on glossy photo paper.
With a 14 mm hollow punch I punched them out and covered them with plastic film.
With some brass washers and silicon glues I glued them on top of the pusch buttons.
After this I started to solder evrything together. (See photos below)
The Nokia headset was connected back to the cell phone.
The small lever on the right hand set is for switching the phone on and off by its original
push button on top of the phone.
Step 3: The case
On the front case you can see the display cover, the keyboard and switch to power the phone on and off.
I placed the charger inside the case.
The phone works very well and I use it one steampunk conventions to take phone calls via the Aethernet ;-)