Abstract: Apparatus and methods are disclosed for providing privacy on communications systems which include radio links, such as cellular telephone, marine radiotelephone, IMTS, and RDSS systems, in a manner which does not require a scrambler/descrambler at each called party location. The apparatus includes a base module having a call diverter connected to the public switched telephone network through two standard telephone lines. A bypass interface circuit is connected to the call diverter between the connections to the two telephone lines to selectively connect a scrambler/descrambler in series with the two telephone lines.In operation, a mobile telephone, such as a cellular telephone, places a call to the telephone number of the first telephone line to cause the call diverter to place the second line off-hook and supply a dial tone from the second line through the call diverter and the first line back to the cellular telephone.