Source: SR4a, page 331
A datajack allows a user to directly interface with any electronic device via a fiberoptic cable. Datajacks also allow users to slot and mentally access chips, softs, and BTLs. Datajacks equipped with their own memory storage for downloading or saving files. Two datajack users can string a fiberoptic cable between themselves to conduct a private mental communication immune to radio interception/eavesdropping.