Featured Iwatsu Field Phone…age and in Japanese/English?

Good morning everyone! We have this field phone that appears to be made by Iwatsu. Wondering if you can help with age? Perhaps the 1970s? I find it fascinating that it is in both Japanese and in English. Does that mean that it was used in both countries? Cannot find the field phone by its identification number. Anything you can help with it will be greatly appreciated.TIA

 

Found 3 others:
https://www.dubizzle.com.lb/ad/vintage-pt-63-made-in-japan-not-negotiable-ID115635775.html

"More than 50 years old military phone"

and

https://aucview.aucfan.com/yahoo/p1054429215/

But no info regarding the use in both countries.

And this one
https://jp.mercari.com/item/m82560169606
with just the Japanese text, but the on/off switch is in English


And:
info-tme@iwatsu.co.jp

 

I would guess the 63 is the date. I doubt this was military.

 

On Ebay there's a PT-81, with the info that it's from the 50s, but no idea if that's correct. The instructions for that phone are for the PT-81, PT-81s, PT-82 and PT-82s, so possibly the number is really just the model no. And PT seems to be 'Portable Telephone'

I concur
On X there's this PT-72,
with this text (according to Google Translate):
"Mobile phone PT-72
Unlike today's mobile phones, they were created at the time to serve as a means of communication at construction sites, etc., and for power/railway-related maintenance communications. This is a telephone that is carried around the premises and used by connecting to an installed line."

And of course there's a year mentioned on the signs of the other 3 phones, and not on the PT sign

 

You’re awesome! THANK YOU!

 

Thank you to everyone!!