Gray 23B
Gray #20B, very similar to the #23 but with a deeper coin drawer. This paystation mounts to the front of an antique wood wall telephone in place of the transmitter assembly. The unit has a grid of holes in the backboard that are used to line up with the original transmitter mounting holes in the front of the phones case. Basically once this is installed on the phone it converts it into a payphone. View my article Gray 23B Coin Collector
