A bridge for linking a first communications network to a second communications network is taught. The bridge comprises a first bridge module linked to the first communications network and a second bridge module linked to the second communications network. The first bridge module is linked to the second bridge module by only an analog audio link and a General Purpose Input Output call negotiation signalling link such that generic digital data cannot effectively pass between the first communications network and the second communications network through the bridge elements. There is also provided a network terminal for connection to a network connected to the bridge and communications system comprising the bridge and first communications network.