Some interfaces for hardware image display devices are also available, although a general display interface is not yet included in the system. Only the IIS model 70 and 75 are currently supported by NOAO. Interfaces for other devices are possible using the current datastream interface, which is based on the IIS model 70 datastream protocol with extensions for passing the WCS, image cursor readback, etc. (see the ZFIOGD driver in unix/gdev). This is how all the current displays, e.g., ximtool and saoimage, and the IIS devices, are interfaced, and there is no reason why other devices could not be interfaced to IRAF via the same interface. Eventually this prototype interface will be obsoleted and replaced by a more general interface.