That is basically a original car phone you have there. From what I've been told (I have a old one but it appears a bit newer than yours) you would select a frequency on the controller which would connect to a tower, you'd get a dial tone and use the rotary dial like a old school telephone.
100% useless more or less these days. I'll see if I can find mine and post s picture.
Sidenote. Do you have the other parts of it? You should have a rectangular box if I'm not mistaken which is the actual radio part. Any model numbers on anything ? Or fcc id label?