The typical method of doing this is using the present direction of the tank gun as a reference point and moving it onto the target from there using up/down left/right commands, though clock-references may also be used.
[5] British tanks deployed in the Normandy campaign in 1944 were also equipped with them, though they were often knocked out of action as they were exposed to artillery and mortar fire.
[13] During the battle of Tarawa, deployed Sherman M4 tanks carried infantry phones housed in rear-mounted bags.
[14] M4A3 Shermans deployed during the Korean war included tanks with phones housed in rear-mounted boxes.
[18] In the "Mod B" program these were raised and moved away from the rear mud-guard as to avoid it becoming tangled with undergrowth whilst the tank was driving through thick jungle.
[20] The infantry phone was thought to lead to infantrymen speaking on it becoming exposed and a target for enemy forces.