Accessing Modicon PLC with a substitute of USB-Modbus Plus?

[axios]

Hello all,

Connecting to a Modicon PLC a laptop with old DOS Software on Windows XP and a USB-Modbus Plus Converter is used.
Is it possible to access the Modicon with some different USB Device, not the USB-Modbus Plus Converter from Schneider?
Is Modbus plus a proprietary protocol built on Modbus?