| Signal | Connected To | Notes | |
| +5 | |||
| +5 | |||
| U425-13 | Cassette tape out | ||
| connected to P401-6 | |||
| No connection | |||
| R/W | U401-34 | unbuffered CPU read/write | |
| U414-6 | |||
| BD0 | U419-3 | To Input/Output Board | |
| BD1 | U419-5 | To Input/Output Board | |
| BD2 | U419-7 | To Input/Output Board | |
| BD3 | U419-9 | To Input/Output Board | |
| BD4 | U419-12 | To Input/Output Board | |
| BD5 | U419-14 | To Input/Output Board | |
| BD6 | U419-16 | To Input/Output Board | |
| BD7 | U419-19 | To Input/Output Board | |
| D0 | U401-33 | To Input/Output Board | |
| D1 | U401-32 | To Input/Output Board | |
| D2 | U401-31 | To Input/Output Board | |
| D3 | U401-30 | To Input/Output Board | |
| D4 | U401-29 | To Input/Output Board | |
| D5 | U401-28 | To Input/Output Board | |
| D6 | U401-27 | To Input/Output Board | |
| D7 | U401-26 | To Input/Output Board | |
| GND |
Copyright © 1992 Donnie V. Savage
All Rights Reserved.