AMX 20 Wireless Speakers (400-1364) Addendum Faxback Doc. # 15851 The transmitter for your AMX 20 Wireless Speakers includes a CHARGER jack and indicator. This jack is for charging the Optimus PRO 100 Wireless Headphones (Radio Shack Cat. No. 33-1145). Do not plug any other deice into this jack. (ALL-07/12/95)