O2 Parallel Port:
Why does the parallel port look different than the Indy?
The O2 parallel port supports the new IEEE standard 1284C for parallel ports, including bidirectional I/O.
What are the pinouts on the parallel port?
O2 uses the standard IEEE 1284-C cable. The current Centronics 25-pin connector on host side is called IEEE 1284-A and 36-pin connector on printer side is called IEEE 1284-B. The O2 uses a 36-pin mini-connector called IEEE 1284-C which has different pin assignments than type A and type B. The type-C cable has been available for a while and should be available from most of the computer supply stores.
The IEEE 1284-C specification is described in IEEE Std 1284-1994 document "IEEE Standard Signaling Method for a Bidirectional Parallel Peripheral Interface for Personal Computers" page62-63. Customers requiring more details will need to order a copy of IEEE std 1284-1994 document or they can access FarPoint for some information.
Here is an IEEE 1284-C pin assigment in Compatible (Centronics) mode:
| 1284C Pin | Signal Name | Signal Description | Centronics Pin |
| 1 | BUSY | ||
| 2 | SELECT | ||
| 3 | nACK | ||
| 4 | nFAULT | ||
| 5 | pERROR | ||
| 6 | DATA 1 | ||
| 7 | DATA 2 | ||
| 8 | DATA 3 | ||
| 9 | DATA 4 | ||
| 10 | DATA 5 | ||
| 11 | DATA 6 | ||
| 12 | DATA 7 | ||
| 13 | DATA 8 | ||
| 14 | nINIT | ||
| 15 | nSTROBE | ||
| 16 | nSELECTIN | ||
| 17 | nAUTOFEED | ||
| 18 | Peripheral logic HIGH | ||
| 19 | GND | signal ground (BUSY) | |
| 20 | GND | signal ground (SELECT) | |
| 21 | GND | signal ground (nACK) | |
| 22 | GND | signal ground (nFAULT) | |
| 23 | GND | signal ground (pERROR) | |
| 24 | GND | signal ground (DATA 1) | |
| 25 | GND | signal ground (DATA 2) | |
| 26 | GND | signal ground (DATA 3) | |
| 27 | GND | signal ground (DATA 4) | |
| 28 | GND | signal ground (DATA 5) | |
| 29 | GND | signal ground (DATA 6) | |
| 30 | GND | signal ground (DATA 7) | |
| 31 | GND | signal ground (DATA 8) | |
| 32 | GND | signal ground (nINIT) | |
| 33 | GND | signal ground (nSTROBE) | |
| 34 | GND | signal ground (nSELECTIN) | |
| 35 | GND | signal ground (nAUTOFEED) | |
| 36 | Peripheral logic HIGH |