Re:Um (Score 1)

(oh you can't get into the out of band signalling other then to dial

Dialing a phone is in-band. Touchtone travels in the same band as your voice. It's up to the Class 5 to detect those digits and set up a call digitally.

and thats with isdn which uses isup for its out of band.

ISDN uses Q.931 for call control, not ISUP.