Interface Cards
StarTech.com 4 Port USB to Serial RS232 Adapter - DB9M - RS232 Extension - Serial to USB (ICUSB2324)
Add four RS232 Serial ports to any notebook or desktop computer using a single USB port USB to Serial USB to RS232 USB to DB9 USB to Serial Adapter
https://www.bizrate.co.uk/iocontrollers/startech-com-4-port-usb-to-oid7350907525.html
