The driver is the Microsoft "Prolific Serial/USB" obtained automatically when I updated the USB driver.

I admit I'm having major problems with the USB ports (even the mouse becomes unrecognised). The PC is old (2005 vintage HP Pavilion).

I do not know the brand of serial adaptor.

Home: BDP-103,G61R, HD621, Quad520f, 2xInnersound amps, 3xQuad ESL-63s, 2xJL Fathom F112 V1 subs, 2x Gradient SW63 subs.
iFi Zen Stream , Audeze LCDi4.