Switch grid
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Switch grid is an informal term for pre-constructed switch assemblies where all the switches are formed as a single unit in the factory. Such units remove the need for a mounting plate. There are no individual switches: a single plastic frame holds the contacts and supports the sliders for all the keys.
In the case of Hi-Tek Dovetail Series, a compromise was reached, where the central keyboard area is provided as a fixed-size part, and peripheral keys are added via separate modules that connect in via dovetail joints. This increases the flexibility offered to customers without resorting to loose switches. For larger keyboards, groups of key positions (e.g. function keys or a numeric keypad) may be catered for by small multiple-switch modules or mini-grids.
Switch grids could be sold to a customer for placement onto a PCB; customers wishing to create a single-board computer (such as the Acorn Atom) where the keyboard was an extension of the motherboard needed only place the grid onto the PCB and apply solder, thus simplifying their manufacturing process.
One obvious drawback to this approach is the inability to swap out a single switch. Hi-Tek provided spare switch components (sliders and springs) along with tools required to replace broken parts within a switch position, allowing a grid to be repaired.
Examples
MEI Sabrecoil seen from below showing the terminals (Acorn Atom)
Hi-Tek High Profile grid (DEC VT100)
Hi-Tek Dovetail Series grid with attached discrete switches (HP 9816)
Stackpole switch grid, standard type (Intel iPDS)
Stackpole switch grid, low-profile type (Lear Siegler ADM 11)
