Usage: PORT/A,DELAYTICKS/N PORT/A is the name of the message port to wait for. This argument must be provided. If the name includes spaces you need to enclose it with "". Consider that Amiga-OS port names are case sensitive ! DELAYTICKS/N is the delay time between the single FindPort() calls. The value given must be the number of 1/50 seconds (=1 tick). Defaults to 0 (behaviour of the original WaitForPort command). 25 is probably a good value here. Example: NewWait4Port MIAMI.1 10 ; waits for MIAMI.1 port to appear. It checks its availability every 10/50 second (=200 milli seconds). If you start NewWait4Port without any arguments Amiga-DOS will show you the template and ask you for input. If you input a ? now you will get a more detailed explanation of the arguments. You can cancel NewWait4Port by sending a CTRL_C break. This can be done by pressing <Ctrl><c> or by the following commandline: break `status COM=newwait4port` C Note that it can take up to DELAYTICKS time for the program to quit as the program cannot quit within a Delay() call.