Pericom M Series keyboards

Pericom M Series
Switch	ITW Magnetic Valve low-profile
Sense method	Magnetic induction
Protocol	Serial (1200 baud)
Keycaps	Dye-sub PBT

The Pericom M series of keyboards were bundled with a number of different Pericom graphics workstations in the late 1980s. The example in the infobox, an MX7100, was manufactured in 1988.

The series, as far as is known, shares the same construction. The keyboards use white ITW Magnetic Valve low-profile switches, and have thick, dye-sublimated PBT keycaps. They also have a rather loud buzzer, and a bank of LEDs inbetween the function row and alpha block. The keyboard uses a 1200 baud serial protocol ¹⁾

The PCB is marked “PERICOM PLC” but appears similar to other ITW Magnetic Valve circuit boards, therefore the original manufacturer of the keyboard module is currently unknown. However, it is reasonable to assume that the cases were manufactured by Pericom.

The series contains a few variations, mostly differences in keycap legends, but also the presence or absence of additional keys in the navigation cluster and numpad area. The full extent of the series remains unknown, with only a few documented samples.

Known variants include:

• MX7100 - a gold key variant with seven additional switches between the function row and row 1 in the navigation cluster.

• MG200 - a non-gold key variant otherwise identical to the above.

• MG600 - a non-gold key variant with five additional switches in the lower nav cluster only.

• A variant with unknown model number which has no additional switches and unique sublegends on the keycaps.²⁾

The keyboard consists of two parts, a top and bottom case, as well as the internal assembly. The bottom case is a thick steel plate, also containing the flip-out feet, which secures to the top case with screws both on the bottom and rear of the case. The top case is a single piece of moulded plastic with what appears to be a largely decorative grille.

The keyboard module itself consists of a double-sided PCB with mounting plate, which secures into the top case with six screws. Several switch types are present, including the standard, no-return spring type, a LED switch on the 'Lock' key, and a spacebar switch variant that also has an internal return spring.

The keycaps, as previously mentioned, are thick dye-sublimated PBT with a rubber sleeve fitted around the keycap mount that provides tacility and return force. Legends vary extensively with model, with potential sublegends, front printing and custom legends.

Photograph “Testing_Terminal” used under a CC-BY-2.0 license, © Tony Duell