a hybrid connector system comprising a special jack , a standard coaxial plug effective to make contact with the jack in one mode when inserted therein , and a wire pair plug operable to engage the special jack in another mode when plugged thereinto , the wire pair plug element being adaptable to , or configured especially for , use with shielded twisted pair cables , unshielded twisted pair cables , or ordinary telephone lines . the jack or socket member has first second and third concentric contact members , two of which are arranged to engage respectively , the central and shell contacts of a coaxial cable plug . the third of the contact elements of the socket member is interposed between the first and second contact elements , and the three contact elements are positioned to engage corresponding contact elements of the special plug which , when inserted into the socket completes connection to first and second ones of a wire pair and , optionally , a shield of such wire pair . switch means are arranged to be operated between open and closed conditions by one of the kinds of plugs which the hybrid jack is designed to receive .