Path: utzoo!attcan!uunet!cs.utexas.edu!uwm.edu!uwvax!brownie.cs.wisc.edu!so From: so@brownie.cs.wisc.edu (Bryan So) Newsgroups: comp.sys.ibm.pc.programmer Subject: Accessing COM3 and COM4 Message-ID: <10595@spool.cs.wisc.edu> Date: 16 Jun 90 00:20:00 GMT Sender: news@spool.cs.wisc.edu Organization: U of Wisconsin CS Dept Lines: 11 Somebody must have posted this before, but I am relatively new to this newsgroup, so... can somebody show me the general method to speak to COM3 and COM4? Can I simply service IRQ3 & IRQ4 as if they are COM1 and COM2? If so, how can I distinguish whether the interrupt is raised by COM1 or COM3 (take IRQ3 for example)? Thanks in advance. Bryan So