The first US armoured vehicles to have tank phones attached to them were M4 Shermans deployed during the 1943 Bougainville islands campaign, where tank-crews mounted field telephones to the rear of their tanks housed typically in ammunition cans that were linked to the tank's internal intercom system. A variation on this had the phone connected to the tank by a long wire trailing to a distant phone where infantrymen could use it without exposing themselves to enemy fire. Americans deployed to Europe also made similar modifications to their tanks. During the battle of Tarawa, deployed Sherman M4 tanks carried infantry phones housed in rear-mounted bags. Tanks deployed to Iwo Jima also included infantry phones.