# LPT2, LPT3 **URL:** \ **Category:** Factual Questions\ **Created:** [November 15, 2001, 9:57pm UTC](https://boards.straightdope.com/t/lpt2-lpt3/93614 "2001-11-15T21:57:19Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [November 15, 2001, 9:57pm UTC](https://boards.straightdope.com/t/lpt2-lpt3/93614/1 "2001-11-15T21:57:19Z")
Anyone remember which IRQs they use? ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [November 15, 2001, 10:48pm UTC](https://boards.straightdope.com/t/lpt2-lpt3/93614/2 "2001-11-15T22:48:48Z")
IIRC the ISA printers cards I have installed usually had jumpers to assign IRQ’s (range was usually IRQ 3-9). I don’t think there is any defined IRQ or memory address parameters for LPT 2/3, they simply have to have a usuable addresses defined (whatever they are) and the system will pick them up as additional printer port hardware. It is also possible to share IRQs. In some situations I have installed printer cards with different memory address, both sharing IRQ 7. The only caveat is that you cannot send multiple jobs to both printers at the same time. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [November 16, 2001, 12:58am UTC](https://boards.straightdope.com/t/lpt2-lpt3/93614/3 "2001-11-16T00:58:14Z")
LPT1 used IRQ7. LPT2 used IRQ5. LPT3 was usually found on hercules graphics cards, and could usually be set to use either 5 or 7. Very few printers used interrupts in the days of ISA cards. It was common to assign the IRQs to something else, usually the sound card.