clue , the older friends of myn probebly know it
it was long ago ... long before a cellullar was a thought in our country
This is a Cellular like Cell I have built of my own
I made few cells like this spread arrond the country and
I could have Phone calls from My radio Hand held

At left you can see the Phone Interface (covered with white peaper)
in the middle you can see the Controller board
(again it was long before a Computer was available)
downstairs you can see the Transmitter / Receiver That work Full Duplex