I'm not a 100% clear on the question but here goes.
1st, do you expect a high call volume or light call volume. If more than one call hits a phantom with a dcfw only, the 2nd call will fail usually to the Operator - this is set in LD 15. So if the call volume is high, use an ACD as it will prevent this from happening.
2nd. If you use a phantom, the caller in MMail will recieve the appropriate "greeting". If you use an ACD, the caller will get the PV before the greeting. You try recording a PV of silence, if you don't have silence compression in tools turned on. Also the callers get a 2 second delay before transferring when using an ACD.
Was this what you wanted to know, or were you are instructions on how to program these????