The DEQ macro is used with RESERVE just as it is used with ENQ. It must describe the same resource as the RESERVE and its scope must be stated as SYSTEMS. However, the UCB= parameter is only allowed if the DEQ macro is issued by a task that has previously reserved a device. If the DEQ macro is not issued by a task that has previously reserved a device, the system frees the device when the task is terminated. For a 31-bit UCB address, you must specify the LOC=ANY parameter.