Type JTFB was advertised as a “keyboard” switch in Electronic Engineers Master 1973–74. All types are double-pole, which would make them suitable for two-of-N static encoding. Operating force is given as approximately 130 grams, “perfect for human factor”; this seems too high for touch typing, so these switches may have been designed with calculators in mind. The switches are depicted with standard truncated keycaps and are 18 mm or 0.75″ square. (0.75″ is in reality 19.05 mm.) Rated lifetime is 5 million cycles for momentary switches, and the rated load is 20 mA at 24 V DC. Alternate action switches are rated for 100 thousand cycles. These are presumably mechanical contact, although this is not stated. Shell height is 17 mm.
The models available were:
Type JTFR is a low-profile reed switch, listed as “NEW” in 1973. These switches were rated for 10 W switching, and 10 million cycles lifetime. Total travel is 0.120″ (3 mm), with “progressive operating pressure (0.4 - 0.8 newton)”. The switches are designed for 11⁄16″ spacing, also given as 17 mm (which is 0.67″).
Only one model was listed, JTFR-01G or JTFR-O1G (“0” and “O” are virtually identical in the typeface used).
All material was scanned by Bitsavers unless otherwise noted.
- ITT Jennings advertisement, Electronic Engineers Master 1973–74 Volume 2