The PC122 is a 122-key keyboard that NMB produced since the first generation of keyboards. The keyboard changed over the generations to match the other RT-101 keyboards in the NMB product line. This helps maintain uniformity across all keyboards. There were other variants that were spawned due to creating keyboards for OEMs, those are covered in their respective OEM section.
the following seven main components were introduced:
The keycaps are made out of PBT with dye-sublimated legends. The first generation of PC122 keyboards uses thick legends with shiny keycap sides. Later PC122 use thinner legends and matte/rough sides for the keycaps. Also depending on the version of PC122 some keyboards come with stepped caps where others are not. Where the stepped caps are located depends on the version of the keyboard that NMB was trying to reproduce.
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 first generation of PC122 uses paint along with the plastic case and better represents an IBM F122 by having a rougher texture and round sides. Later versions of the PC122 uses just molded plastic that better represents fourth generation of NMB keyboards.
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 joins the two halves together. The feet that are integrated into the lower case are flush with the lower case when retracted. The earlier versions of the PC122 uses a metal backplate where the feet are located at far ends of the case like in the first generation keyboards. The feet use a bent wire as a spring to make the feet lock into place once fully extended. Later versions use the same feet in the fourth generation of keyboard being made out of plastic and relying on tension from the extruded bottom case.
The PCB is a double-sided PCB with all traces on the backside of the PCB. Early generation of the PC122 uses a PCB where only the mod keys send break codes and all other keys send only make codes. Additionally, the early version of the PC 122 and some later versions require a higher voltage than 5v and have a voltage regulator.
Later versions of the PC122 can have a different protocol and do not work over 5v. These boards can be modified with a control replacement, some additional jumpers and diodes. Most Later versions of the PC122 are XT/AT.
The cable is approximately 1 meter long for the coiled variant and stretches up to 2 meters easily. It contains either a 5pin din, RJ or PS2 connector.
IC and Jumpers