This keyboard was OEMed for ADDS (Applied Digital Data Systems)
The ADDS PC+ is used for the ADDS terminals. This keyboard is unique as it's very close to a standard ANSI 101 layout or ISO 102 layout with the addition of some function keys above the number pad. This keyboard can easily be converted as the protocol is AT which is also unusual for a terminal keyboard.
The ADDS PC+ is made up of the following components:
Switches
Keycaps
Upper Case
Mounting Plate
PCB
Back Plate
Cable
The keycaps are made out of PBT with dye-sublimated legends. The keycaps for the fifth generation include clips on the sides of the keycaps to secure them properly to the switch.
The keycaps on generation five boards contain wire stabs similar.
The upper case is made out of a single piece of beige ABS plastic. The plastic is textured due to the molding process that is used to create the upper case.
The lower case is molded from the same ABS plastic as the upper case. A set of slots are located in the lower case that join the two halves together. The feet that are integrated into the lower case are flush with the lower case when retracted.
The switch plate is made out of stamped steel. The plate has deeper stamping around the switches so that the entire switch plate could be produced with less material. The plate is only coated with a clear coat.
The PCB is a double-sided PCB with all traces on the backside of the PCB. The controllers found on the PCB vary, some later models have been found with both Toshiba and Mitsubishi controllers.
The cable is approximately 30 centimeters long and stretches up to 60 centimeters  easily.