Hello Greg, I have purchased a USB-RS485 Cable Manufacturer: FTDI SerialNumber: FTU6Z938. And I have written a user space program to communicate with my Rs-485 device at the other end.The device at the other end expect 1 address byte with mark parity and rest of the bytes with space parity. Below is the userspace code which I have used for setting the Mark and Space parity bit. // Send the first byte with mark parity- attr.c_cflag |= PARENB; attr.c_cflag |= CMSPAR; attr.c_cflag |= PARODD; tcsetattr(fd, TCSADRAIN, &attr); write(fd, buff, 1); // It writes the address byte // Send the rest with space parity attr.c_cflag |= PARENB; attr.c_cflag |= CMSPAR; attr.c_cflag &= ~PARODD; tcsetattr(fd, TCSADRAIN, &attr); write(fd,buff+1,( length-1)); I can see the Data going out on the Scope when I terminate the userspace program using Control+ C. But the device at the other end is not responding. Kindly tell me Whether It can be done from userspace or I have to modify the device driver. Regards, Raj. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html