05 79 30
|PCB, TX-20 with Clare SF switches|
|23127828-8C||PCB, TX-20 with M7 switches|
TX-20 is a Telex teleprinter from SAGEM. Over its lifetime it has had a variety of colour schemes and keyboard layouts. At least three switch types are known: Clare high-profile reed, Clare low-profile reed, and Cherry M7 Style D. The existence of Clare switches in these products confirms that Style D was designed to be compatible with Clare keycaps. It is not known whether Cherry were used for extra manufacturing capacity, or to reduce costs. Cost reduction would suggest that they would have simply adopted Cherry’s existing switch design and keycaps rather than have Cherry retool.
|LOZB’s spare keyboard||Two-tone blue-grey, with A… key, and Q/A/Z in column 3||Cherry M7, with blue–clear pair for the wide enter key|
|inotarobot’s spare keyboard||Light brown, with A… key, and Q/A/Z in column 2
(a photo of a complete unit was online but has been taken down since I discovered it)
|Clare SF (high-profile reed)|
|Frédéric BISSON’s complete teleprinter||Two-tone blue/grey (additional images of this variant), with ⊕ key, and A/Q/W in column 3||Unknown|
|10ko’s example||Unknown||Cherry M7, with blue–clear pair for the wide enter key|
The Workshop Technical Document (with no date) gives Clare International NV of Tongeren in Belgium as a supplier, but not Cherry. The keyboard is described as comprising “… a set of dust-tight reed contact switches …” The parts list gives the type A keyboard as part 23074795-8, and the type B keyboard as part 23126742-5. Keyboard PCBs 23074345-0, 23077489-3 and 23106892-6 are not the PCB from the keyboard assembly itself, but rather backplane boards within the main body of the unit.
The Clare switch types are as follows:
|Variant||Normal||Low force||Sprung dummy|
|“A” (high-profile reed)||SF6102 (80 gf)||SF6101 (50 gf)||SF6001 (50 gf)|
|“B” (low-profile reed)||SFL6102 (80 gf)||SFL6101 (50 gf)||SFL6001 (50 gf)|