I have a old Windows 98/DOS HVAC Control software program that requires a 9 pin serial port dongle to work. Software (Dos Based) can be installed and run but looks for dongle to allow operation. I own the software but have lost the dongle and as software is now obsolete there is no support or replacement available. Software is on 2 x 3.5" floppy's but can be electronically delivered in zip file. I can upload software to approved bids.
Edit.. Dongle connects to LPT not serial port. Serial port connects to device.