Line Access Test Set 2W/4W The Wilcom Model T318B Line Access Set provides access to 2-wire and 4-wire facilities. Whether used by telephone companies, common carriers, or private networks. The Model T318B enables quick and efficient interfacing of analog transmission facilities. This unit is particularly useful at the network demarcation point where it is used to simulate network functions towards the customer-owned equipment, or to simulate the customer-owned equipment functions towards the network.