Basically I'm using the following code to set the baud rate of a serial port: struct termios options; tcgetattr(fd, &options); cfsetispeed(&options, B115200); cfsetospeed(&options, B115200); tcsetattr(fd, TCSANOW, &options); This works very well. But know I have to communicate with a device that uses a baud rate of 307200. How can I set that? cfsetispeed(&options, B307200); doesn't work, there is no B307200 defined.