The Telephone D Mark V is a Second World War era portable telephone designed for field use in Army formation forward of Divisional Headquarters. In addition to the ability to talk, it provides a call buzzer, a bell indication of an incoming magneto generator call, aural indication of an incoming buzzer call and the ability to communicate by buzzer and key.

Reliable speech could be as much as 14 to 16 miles with D8 cable or 8 to 10 miles of D3 twisted cable. Morse telegraphy could be 25 and 15 miles respectively.