Null Modem Emulator Windows 10
Both of Acamar links require a comm port on the computer. OP needs a comm port on the computer because the application uses a comm port and that can't be changed.
If the application communicates over a serial connection then a comm port is the only way to do it, and the applictions I referred to provide that port. The virtual serial ports that they create can be connected together internally as required to crete the equivalent of a null modem external connection between physical serial ports, which is what OP is tring to do. For example ' Virtual Serial Port Driver creates virtual serial ports and connects them in pairs via virtual null modem cable. Applications on both ends of the pair will be able to exchange data in such a way, that everything written to the first port will appear in the second one and backwards.'
( The one I use with software that only knows how to communicate over a serial port is which is described as 'The Null-modem emulator allows you to create an unlimited number of virtual COM port pairs and use any pair to connect one COM port based application to another. Each COM port pair provides two COM ports. The output to one port is the input from other port and vice versa.' That, and others. Solves the problem that OP has in connecting to that application that only understands serial port communication. Both of Acamar links require a comm port on the computer. OP needs a comm port on the computer because the application uses a comm port and that can't be changed.
Add Modem Windows 10
If the application communicates over a serial connection then a comm port is the only way to do it, and the applictions I referred to provide that port. The virtual serial ports that they create can be connected together internally as required to crete the equivalent of a null modem external connection between physical serial ports, which is what OP is tring to do. For example ' Virtual Serial Port Driver creates virtual serial ports and connects them in pairs via virtual null modem cable. Applications on both ends of the pair will be able to exchange data in such a way, that everything written to the first port will appear in the second one and backwards.' ( The one I use with software that only knows how to communicate over a serial port is which is described as 'The Null-modem emulator allows you to create an unlimited number of virtual COM port pairs and use any pair to connect one COM port based application to another.