The DK424 can not do this on its own. An external device, normally voice mail, is required to do this.

It will do the transfer to an outside number if the system were put into night mode., but not on an ACD overflow condition.

The only real way to get this to work is to get the T1 carrier to allow a hook flash style transfer on the T1, Then it will work rather nicely.

ACD to Voice Mail, Voice Mail does the transfer