This is because the legacy software doesn’t know how to recognize or read USB or Ethernet data - and resurrecting the software engineer that originally coded it probably isn’t an option. The challenge here is different than just converting a serial device’s interface to a USB or Ethernet interface. This can be problematic if you still rely on legacy software applications that communicate through those now non-existent (or very limited) serial ports. In many cases, even if they do, the number of available ports is very limited. Most modern desktop computers and laptops no longer have the old school DB9 RS-232 serial ports (COM ports) that were traditionally used to connect directly to the hardware used in commercial, laboratory or industrial safety and control systems.
