IBM 4019, 4029 Laser Printers
Note: These printers have both parallel and serial interfaces on the same Centronix connector. To use with a
multiplexer, the interface must be set on the printer to "serial" or "RS232".
IBM printer to DCB mux cable
| Signal | IBM
Centronix | Direction | SR RJ45 | SPL
DB25P | Signal |
| TxD | 15 | ===> | 6 | 2 | TxD |
| RTS | 18 | ===> | 8 | 4 | RTS |
| SGND | 19 | ==== | 4 | 7 | SGND |
| RxD | 33 | <=== | 5 | 3 | RxD |
| DTR | 34 | ===> | 3 | 11 | Busy |
| DSR | 35 | <=== | 1 | 6 | DSR |
| CTS | 36 | <=== | 7 | 5 | CTS |