Check out pages 12 and 18 of World of 68' Micros, The - Vol. 2 Number 4, https://archive.org/stream/World_of_68_Micros_The_Vol._2_Number_4_1994-12_FARNA_Systems_US#page/n11/mode/2up <https://archive.org/stream/World_of_68_Micros_The_Vol._2_Number_4_1994-12_FARNA_Systems_US#page/n11/mode/2up>