USB to serial port converter

It is not supposed to be easy.

The software developers would have encountered the problem already and may rather want to replace the dongle or supply a software fix. Contact them.

iawtc - contact the s/w vendor and get a USB key. It should be an easy thing to do.

Are you sure it's not a parallel port? That would take a different converter (USB to parallel...)

Unfortunately many laptops (and desktop PCs) and USB-serial converters don't always implement the serial protocols correctly. I have found that Dell laptops are particularly bad. I have had to use trial & error to find a USB-serial converter brand/model that does work - often it is the cheaper ones, but I don't normally get more than about 1 in 3 to operate correctly.

However, before spending the time & money, do as previously suggested - go back to the software company & ask if they have an alternate solution - many have USB dongles available now.

You can ask FTDI or PROLIFI companies that produce ICs for serial to USB converters .They maybe answer what you could do

The 25 pin connector was a parallel port. The dongle connected to that. The VGA port is not a serial port, although it looks like one. If your new laptop does not have a parallel port, which many don't, you've screwed the pooch. Your only hope is to contact the software company and ask what they have to support laptops in this case.

I previously have found a serial to usb that comes with software that will work

like this but not the one I used

DB-9 Serial Adapter High Speed USB SERIAL RS-232