LPT ports are use for parallel data communication. The name is derived from their original use with printers (LPT—line printer). The original IBM standard LPT port did not provide
bi-directional communications (talk-back) and was designed solely for one-way data streams to a printer.
IBM presents a preset combination of IRQ's and I/O addresses that are shows bellow. Note that IRQ-5 if present, it quickly become the favorite for devices like sound card and other add-on devices.
| Port |
IO Address |
IRQ Number |
| LPT1 |
378 |
7 |
| LPT2 |
278 |
5 |
