I connected my USBSerial Device which is configured as UART to a Linux Machine . The device comes up as MODEM and not as a serial device or COM port . Why?
USB Serial device when configured as UART CDC then it belongs to the CDC ACM Class . A device that belongs to the ACM drivers where intended to work with USB Modem . So any USB device that binds to the ACM driver will come up as MODEM device in Linux machine.
the usbuart enumerates as a serial port. all serial ports on linux are tty ports or similar to modems. you have to open the ttyacmX port (where X is the port number) you write to the port and read from it and it works. If you only have one device then it becomes really easy to script search for the port and then "talk" to it.