The RTS-03 USB to Serial Adapter works with all RT Systems Version 4 software and the original RT Systems serial cables and Yaesu programming cables for radio programming.
RTS-03 adapter forms an RS-232 com port that allows data to flow properly between devices without interference from its electronics. Use it whenever the cable from the manufacturer comes with a DB-9 connection (packet cables, firmware upgrade cables, CAT cables, etc.).
Don't be duped by cheaper USB-Serial adapters. This uses the universally compatible FTDI chipset, rather than the more common Prolific chipset that has been confirmed as not working with several amateur radios.
This adapter WORKS.