There is a manual put out by the Gov't ... they are in many if not all FAA ATC facilites... the manual # slips my mind at the moment, I'm gonna take a look for it and report back. You should be able to find it through the Gov't printing office... if not maybe through ICAO... ???
I'll see what I can find out for you. BTW ... Frankfurt = EDDF
If you have one you really want to know right now post it, I can most likely find it for you.