Within my PXI Chassis, I have a NI PXI 8420 RS-232 Serial card. It has eight Com ports. Right next to it is an NI PXI-8421 RS-485 Serial card with 4 Com ports. When using MAX, if I expand the Serial & Parallel listing under Devices and Interface, I see COM 1 (skips COM2), then COM 3-14, and LPT1. If I select Serial and Parallel, I see all the Resource/Interface names. What is strange (and it's causing me a problem), is that for all except one Com port, the Resource/Interface names seem to match (i.e. COM3 is associated with ASRL3::INSTR). The one that differs is COM10 - it has an ASRL15::INSTR. This is messing up my algorithm that uses the array returned by VISA Find Resource. COM port 10 should have an iterface name of ASRL10::INSTR. Is there a way to change the interface name? I've tried Tools::NI Serial::Recover Unused Com Numbers, but it didn't help.