There are several interface converters available from well-known manufacturers including Advantech, Moxa and Hirschmann, for example. Working in a variety of settings, these devices ensure that communications can still take place even if different, incompatible interfaces are connected. For example, engineers wishing to connect via an RS-232 port but who only have an RS-422 or RS-485 port on their device will require a serial type of interface converter to allow them to connect. Likewise, a serial interface converter which can connect to fibre optic connections from something like a 4-pin terminal block is often a requirement of network engineers when working in the field. Oftentimes, a physical serial port is the only way to connect to certain devices; thus, an interface converter is essential for remote connections via a secondary, Internet-enabled system. Many interface converters today are designed as simple 'dongles' which are plugged into a serial port with another interface configuration at the disposal of the user on the other side. As such, both male-to-male and female-to-female interface conversion devices can be tracked down. In addition, many types of Universal Serial Bus sockets are used in interface converters with serial ports. These allow a conventional USB port to be added to virtually any sort of information technology system providing a high degree of versatility.