Point to point communication is the most common application for Westermo products. In its simplest form, it consists for example of a PC connected to a serial printer. In more complex systems, it can be an entire star network with numerous point to point connections. The advantage with point to point communication is that it eliminates the risk of data collisions and that the system is less vulnerable since a fault in a single line will not affect traffic between other units. It also has the disadvantage of being more expensive to install and more complex to change and expand. The communication between two short haul modems requires a 4-wire twisted pair cable and offers a transmission range of up to 18 km (depending on data rates). If there is only a 2-wire cable available it is possible to use our telephone modems to provide transmission ranges of up to 25 km. It is also possible to use our interface converters (RS-485) for 2-wire transmission but in this case it is only possible to communicate half duplex.