[en] This report contains the contributions to the 1980 Wire Chamber Conference at Vienna concerning the JADE JET-Chamber. Part 1: The principle of the jet-chamber, a pictorial driftchamber serving as the central track detector of the JADE experiment at PETRA is briefly reviewed. In this chamber, up to 48 points are measured along each track. At each point the space coordinates R, diameter, Z and the energy loss dE/dx of charged particles are recorded. The present status of the space resolution and of energy loss measurements is described. Experience during mine months of operation is reported. Part 2: Pattern recognition programs developed for the jet chambers of the JADE experiment are described. A method is presented which allows a fast determination of the event vertex a long the beam direction without prior track finding. The track finding itself starts with the complete set of measured points per track and reduces this information to line elements, track elements and tracks. The efficiency obtained so far for jet events with a high track density is 97% per track. In addition a graphics program is described which allows interactive guidance of the pattern recognition. (orig.)