Free Ports

When a link that has been assigned a dynamically allocated port ends, DMTMANEX posts the free port ECB for the AST task. This tells the AST task that a dial-out port is now available. The REX task may also post the free port ECB when a PORT command defines a dial-out port.

When this ECB is posted, the AST task determines if any links are held in dial-queue status. If it finds a dial-queue link, the AST task assigns the free port and attaches the link driver task.