Object is a suitcase-sized box of electronics with four, 36-pin parallel-port connectors labelled "Keyboard Channel 0/1/2/3". This apparently is the CPU providing service to the four small keyboard/display units parts BCDE. Of the display units, parts B and E are models 310 and 320 respectively, and have math function keys and toggles to control summation. Parts C and D are simpler models 300 with only basic calculator keys.