Have seen photos of and read about phones that were attached (usually inside old ammo boxes) on the rear of US tanks towards the end of the war to allow supporting infantry to easily communicate with the tank commander without exposing themselves to fire.
However, I can't get hold of the book I saw them in and was wondering if you resourceful chaps have any reference photos of one? If possible on the back of a sherman?
As always all help and suggestions are greatly appreciated!

James