I checked several USB/RS232 adapters available online, but they all had wires for the CTS and DSR lines. To control TS-2000 from SkyRoof, you need an adapter that has these two lines connected to the RTS and DTR respectively on the transceiver-side connector. This is easy to fix though, if you have a sharp knife and some electrical tape, just cut the wires and re-connect them as described in
this posting. After this surgery any USB/RS232 adapter will work as required.