USB¶
MT2503 chipset provide USB 1.1 interface with CDC(ACM) profile. USB port can be used to interface device with a USB host for communication.
Only Following GSM module provide USB Access:
MC20U
SIM868
USB serial port is registered as a device file /dev/ttyUSB0 which supports standard system calls for IO operations and termios API for serial port parameter controls.
There are no USB specific APIs.
Refer UART documentation for access to serial ports