The noise is very noticeable. Not faint at all. I haven't tried another computer, but, I control my Icom r-75 with RS-232 and have notice no interference. The cable is an INMAC cable a few years old and may not be well shielded. I will try it with my laptop and if it still occurs I will get an RS-232 to USB cable and try that. Tnx es 73, Chuck