 In modern serial ports using a UART integrated circuit, all settings are usually software-controlled; hardware from the 1980s and earlier may require setting switches or jumpers on a circuit board.One of the simplifications made in such serial bus standards as Ethernet, FireWire, and USB is that many of those parameters have fixed values so that users cannot and need not change the configuration; the speed is either fixed or automatically negotiated.Often if the settings are entered incorrectly the connection will not be dropped; however, any data sent will be received on the other end as nonsense.