Are you using a USB to Serial adapter? When I had my old Hicom 150 (which became the original 3000) it was VERY anal retentive about the serial connection. I had to keep an ald laptop around that had a real serial port. At that time I tried several brands of USB-Serial and none of them would let me admin that system. I have since started using Black Box USB - Serial, and while more expensive they seem to be more compatible with my applications. I don't have the 150 anymore - I upgraded everything last year, so I never tried it without the old laptop. I also used the cable they shipped with the 150 because I have had issues with cables, but others have stated it doesn't matter which cable you use.