JOSS (JOHNNIAC Open Shop System) was a new computer language, which together with new remote terminals, attached to RAND's JOHNNIAC mainframe computer, comprised one of the first time sharing computer systems.
This RAND document from RAND contains more information about the language and using the JOSS system. Of particular interest to us is the special console designed for JOSS, which is described in detail in this RAND report. The JOSS console comprises a modified IBM 731 "input-output" electric typewriter attached to a specially designed control logic which interfaces between the typewrite and a full-duplex communication channel. Figures 1 and 2 come from this RAND report showing the console: the typewriter on top of the control box.
The museum contains an instance of the JOSS console control box. Figures 3 and 4 show the front and back sides. Figure 5 shows one of the 50 cards containing in the control unit's logic. This appears to use diode logic. Also in Figure 5 we see the RAND label and serial number of our controller. Figure 6 show some information pasted to the side of the controller, and Figure 7 show some of the status lights on the top of the controller.