 The designs for the devices are owned by Ubicom (formerly Scenix, hence "SX").The SX dies were manufactured by Ubicom, who sent them to Parallax for packaging.Ubicom had made processors with 18, 20, 28, 48 and 52 pins, but because Parallax did not have packages for 18 and 52 pins chips, the SX-18 and SX-52 were discontinued.