On 11/28/2023 6:46 AM, Andy Durbin wrote: > Isn't it true that the KAT500 USB cable uses RS-232 protocol but TTL signal levels? T RS-232 is NOT a matched transmission line -- it's a low-Z source and high-Z input. The limitation on line length is not signal strength, but rounding of the pulses by cable capacitance. 73, Jim K9YC