Maximum Number of LPT and COM Ports

This article was previously published under Q100111

The maximum number of COM and LPT ports that Windows NT supports is 256. This is a limitation in Control Panel and does not represent a limitation of the hardware platform. In both Intel x86 and MIPS machines, the number of COM and LPT ports is only limited by available interrupts, I/O addresses and, ultimately, 4,294,967,295 (32 bits).