Northen Telecom PT500 (Kari-Fone)

[Spanish_phones]

Hi there!

I have just bought this rotary phone. Here in Spain, American phones are really difficult to find.

I bought it because, in my opinion, it's an uncommon model, because it's a 2500 model, but wiht a rotary dial.

What I surprise I had when I opened the phone to rewire the phone to make it to work, when I discovered it's not a usual phone: It has batteries, a charger... and a lot of electronics...

Any idea of what is this? How could I adapt it to an ordinary line? Or is it a wireless model?

Thank's in advance for your help,

Iñaki

[countryman]

Now that's cool. It must be one of the first cordless phones, made to help disabled persons! I tried to copy pages from Google books -> Bulletin of prosthetics research 1977!
Google finds it by the words: Kari fone new york.

It might be a Find of the Month?!

Edit to add a TinyURL.com link:
https://tinyurl.com/r8pdzbg

[Spanish_phones]

Thank you so much!

Now I have to figure how to make it work, because I don't have the base unit to make it work wireless

[countryman]

Mr. Darwin would have loved your find. It's the missing link in the evolution of phones...

[HarrySmith]

That is an amazing pice of telephone history. I would not change a thing! Keep it original. Also try contacting the seller, maybe he has the base unit but does not know it!

[Spanish_phones]

I understand that modifying the phone would be a sin, but instead of wire it, at least I would like to make it work, but I'm only good wiring traditional rotary phones... this one looks like a radiotelephone...  Any help would me a huge step forward for me in this new proyect

[Jim Stettler]

I would buy a clear Cortelco/ ITT 2500 set  and try to out switch the housing. It would be pretty interesting in clear. You would need to keep the faceplate.

Here is an example currently on eBay
https://www.ebay.com/itm/274150152010

The photo is from the auction.
These come up every month or so.
JMO,
Jim
BTW: whenever I swap to clear housings, I keep the original so I can switch back.

[Jim Stettler]

I have the Trimline style cordless. It is called the  porta call. Figure 6 from the google book post.
Mine is a Red one. I will  post a photo when I find it.
Jim

[countryman]

I have tried to research more but in fact this medical journal seems to be the only reference of a Kari-Fone in our modern wwworld until Iñaki's find.
That's crazy - one should expect the idea would have been discussed in electronics magazines. It's practical use is too obvious from today's  point of view.
Googling "Porta call" I found this reference:
https://tinyurl.com/portaphone - in "American Bar Association Journal"! That makes sense. I wonder if it is the same thing as the Kari phone? Maybe the latter brand name was created for the distribution in the medical supply market after other customers failed to appear?

Iñaki, while it might be possible to make this phone operational, this would take some serious radio engineering, even more so without the base unit that came with it. Maybe a radio collector (forum) could help. Some radio amateurs (hams) are also very good at engineering.

P.S. I now figured out the tinyurl thing. Thanks Jim 

[Spanish_phones]

Thank you so much!

I will try... but if no other person gives me some clues to make it work, it would be just a non-functioning piece of history... not so bad at all

[twocvbloke]

That's a pretty neat idea, not entirely sure how it'd work myself, but I'm no radio person (I barely know what to do with my CB radio aside from try and listen in, not that many people round here still use them), if the base station can't be found, it's definitely worth displaying, as it's certainly a unique creation...