This information was taken straight from section 13.4 of the Atari 8 bit Frequently Asked Questions with the exception of the 825 printer information included at the end.
Serial I/O (SIO) Port (all machines): 2 12 o o o o o o o o o o o o o 1 13 1. Clock Input 8. Motor Control 2. Clock Output 9. Proceed 3. Data Input 10. +5V/Ready 4. Ground 11. Audio Input 5. Data Output 12. +12V (400,800 only. 1400XL/1450XLD?) 6. Ground 13. Interrupt 7. Command Cartridge Slot ("Left" slot on all machines; "Right" slot on 800 only): A B C D E F H J K L M N P R S 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1. ~S4(Left) R/~W late(Right) A. RD4(Left) B02(Right) 2. A3 B. GND 3. A2 C. A4 4. A1 D. A5 5. A0 E. A6 6. D4 F. A7 7. D5 H. A8 8. D2 J. A9 9. D1 K. A12 10. D0 L. D3 11. D6 M. D7 12. ~S5(Left) ~S4(Right) N. A11 13. +5V P. A10 14. RD5(Left) RD4(Right) R. R/~W 15. ~CCTL S. B02 Enhanced Cartridge Interface (ECI) (130XE, 800XE and European 65XE only): A B C D E F H 1 2 3 4 5 6 7 A. Reserved 1. ~EXSEL B. ~IRQ 2. ~RST C. ~HALT 3. ~D1XX D. A13 4. ~MPD E. A14 5. Audio F. A15 6. ~REF H. GND 7. +5V Monitor Jack (all but 400, N. American 600XL, XE Game System, SECAM systems): 3 1 5 4 2 1. Composite Luminance 2. Ground 3. Audio Output 4. Composite Video 5. Composite Chroma (not on 800XL,1200XL; grounded on 600XL) Monitor Jack, SECAM systems: Jer Sobola, mailto:jsobola@ramserwis.com.pl provided this pinout: V 5 1 3 4 2 6 1 +12V DC 5mA max 2 Audio 1 output 3 Audio 2 output 4 Video output 5 GND 6 +5V 100mA max Amplitude Audio 2 is about 6 times closer than Audio 1 Power Adapter Plug (all but 400,800,1200XL,1400XL,1450XLD): 7 6 3 1 5 4 2 1. +5V 2. Shield 3. Ground 4. +5V 5. Ground 6. +5V 7. Ground Controller Port (4 on 400/800, 2 on all others): 1 2 3 4 5 6 7 8 9 CX22 trackball meanings from Steve Wallace: 1. (Joystick) Forward Input X Direction 2. (Joystick) Back Input X Motion 3. (Joystick) Left Input Y Direction 4. (Joystick) Right Input Y Motion 5. B Potentiometer Input 6. Trigger Input / Light Pen Input. Port 4 only on 400 7. +5V 8. Ground 9. A Potentiometer Input Parallel Bus Interface (PBI) (600XL and 800XL only): 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 1. GND ground 2. External select 3. A0 Address output 4. A1 5. A2 6. A3 7. A4 8. A5 9. A6 10. GND 11. A7 12. A8 13. A9 14. A10 15. A11 16. A12 17. A13 18. A14 19. GND 20. A15 21. D0 Data (bidirectional) 22. D1 23. D2 24. D3 25. D4 26. D5 27. D6 28. D7 29. GND 30. GND 31. Phase 2 clock output 32. GND 33. NC Reserved 34. Reset output 35. (IRQ) Interrupt request 36. Ready input 37. NC 38. External decoder output 39. NC 40. Refresh output 41. Column address output 42. GND 43. Math pack disable input 44. Row addr strobe 45. GND 46. Latch read/write out 47. NC (+5V on 600XL only) 48. NC (+5V on 600XL only, used to power 1064) 49. Audio input 50. GND R1: Serial port DB9P (850 Interface Module): 5 4 3 2 1 ____________________________ 9 8 7 6 / DB25P 1. DTR - Data Terminal Ready (out) + 20 2. CRX - Signal (carrier) Detect (in) + 8 3. XMT - Transmitted Data (out) + 2 4. RCV - Received Data (in) + 3 5. GND - Signal Ground + 7 6. DSR - Data Set Ready (in) + 6 7. RTS - Request to Send (out) + 4 8. CTS - Clear to Send (in) + 5 No connection to shield + Frame - to the shield wire R2: Serial port (850 Interface Module): 5 4 3 2 1 9 8 7 6 1. DTR 3. Send Data 4. Receive Data 5. Signal Ground 6. DSR R3: Serial port (850 Interface Module): 5 4 3 2 1 9 8 7 6 1. DTR 3. Send Data 4. Receive 5. Signal Ground 7. RTS 8. -8 Volts R4: Serial port (850 Interface Module): 5 4 3 2 1 9 8 7 6 1. Send Data + 3. Send Data - 7. Receive Data + 9. Receive Data - (20 mA) P: Parallel port (850 Interface Module) DB15P: 8 7 6 5 4 3 2 1 ____________________________ 15 14 13 12 11 10 9 / 36 pin Centronics (male) 1. Data Strobe + 1 2. D0 + 2 3. D1 + 3 4. D2 + 4 5. D3 + 5 6. D4 + 6 7. D5 + 7 8. D6 + 8 9. Data Pull up (+5v) + 10. - + 11. Ground + 16 12. Fault + 32 13. Busy + 11 14. - + 15. D7 + 9 No connection to shield + Frame - to the shield wire P: Parallel port (XEP80 Interface Module): 13 12 11 10 9 8 7 6 5 4 3 2 1 25 24 23 22 21 20 19 18 17 16 15 14 1. Strobe 2-9. Parallel Data 10. Not Used 11. Busy 12-17. Not Used 18-25. Ground 825 printer connection: The Atari 825 printer has a 40 pin edge connector on back for a data cable connection. This connector serves the same function as the more common centronics connector, Atari just chose to use a different connector. I found it easiest to make an adaptor to convert the 40 pin edge connector to a 36 pin centronics connector. Note that because there are 4 extra pins on the printer, pins 37, 38, 39, and 40 will be unused. Using ribbon cable and crimp-on connectors, align pin one on the 40 pin connector with pin one on the centronics connector. Note that this does not make a 1:1 connection on all pins. The centronics connector orders the pins 1, 19, 2, 20, 3, 21, etc. while the edge connector has the pins in order from 1 to 40. Using ribbon cable connectors and aligning pin one to pin one automaticly gives the correct pin ordering, allowing for a simply made adaptor. With this adaptor the 850 printer cable mentioned above may be used to connect the 825 printer.Back To Main Page