ADDS ASCII

Overview

This keyboard was OEMed for ADDS (Applied Digital Data Systems)

The external appearance of the ADDS ASCII also known as the ADDS 2000 is unique. The keyboard was OEMed by NMB and many other companies as well. The keyboard is a terminal-based keyboard therefore, it speaks two different protocols. One of the protocols is AT-based. This protocol has been used to make a converter see the Protocol section.

Summary

The keyboard’s layout is unique to this keyboard and is only found on another version of this keyboard that is commonly found under the NCR branding known as the NCR 4590:

Switches
Keycaps
Upper Case
Mounting Plate
PCB
Back Plate
Cable

Switches

Keycaps

The keycaps are made out of PBT with dye-sublimated legends. The keycaps for the ADDS ASCII include clips on the sides of the keycaps to secure them properly to the switch. These caps are

Bottom of Keycap

Upper Case

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 case also contains a see through piece of plastic so that different sheets which contain functions that the function keys could perform.

Lower 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 lower case contains a single foot which can fold away flush into the bottom case.

Switch Plate

The switch plate is made out of stamped steel. The plate is painted with a think black paint and then coated with an oil like liquid to help prevent rust from occurring.

PCB

The PCB is a double-sided PCB with all traces on the backside of the PCB. The PCB sometimes can contain a voltage regulator that will drop the terminals output voltage from 9V to 5V. This can be removed if it's no longer required.

Cable

The cable is approximately 1 meter long for the coiled variant and stretches up to 2 meters easily. It contains a molded 5 pin din connector with 6 pin headers using a molex connector on the PCB.