While I was aware that during 1944, the British started fitting Infantry telephones to some tanks, I did not know the details of the installations.
I stumbled across this information while researching a different piece of equipment.
The March 1944 instructions for the Churchill II through VII installation can be found here:
https://heritage.canadiana.ca/view/o...eel_c5818/3312
The April 1944 instructions for Sherman V (missing some of the drawings) can be found here:
https://heritage.canadiana.ca/view/o...eel_c5818/3308
In August 1944, an instruction was issued to extend the modifications to Sherman I, II, and III:
https://heritage.canadiana.ca/view/o...eel_c5818/3306
A few years ago I saw a “Microphone and receivers headgear assembly” which had been modified into a rather crude looking handset. I now realize that this was the approved modification to provide a tank-infantry telephone.
There is currently an example for sale on eBay.uk which seems to conform exactly to the instructions:
https://www.ebay.co.uk/itm/175307176...=&toolid=10050
Attached are an image from the modification instruction, and a couple images from the eBay listing.