DT wiki:
wiki/IBM_Model_FIBM Personal Computer keyboard
The keyboard of the 1981 IBM PC 5150 is commonly referred to as the "PC XT" keyboard, although it predates the XT. It was based on the Datamaster keyboard, but was mounted in an external case and used a unidirectional serial connection with a DIN-5 connector. When the PC was released, the keyboard was acclaimed for its touch, but its layout was criticized for having many oddly shaped keys placed close to each other. The US English layout variant had the part number 1501100. The ISO German layout variant had the part number 1501102.