This whole thread is mixing up various versions of the A320.
1)There are A320s without digital AMUs that can be recovered as mentioned by Nattrackalpha and Busav8r - which I hope everyone knows about, basic stuff.
2)There are A320s with digital AMUs that will NOT have ANY functional VHF/HF/SATCOM/ACARS functional with DC ESS fail. No matter what switching you do! Here is a re-post of the FCOM ref above from an affected aircraft:
<<<In the case of an ELEC DC ESS BUS FAULT, the audio cards of the AMU are lost. Since all cockpit
mikes and headsets are connected to the AMU, all audio means of communication (VHF, HF and SATCOM )are lost.
The use of VHF 2 or 3 do not allow to recover communications.>>> In otherwords no matter what switching you do, you've lost them.
3)There are A320s with digital AMUs that from manufacture or retrofit will have comms capability with DC ESS FAIL using the usual method.
Last edited by tom775257; 4th Feb 2013 at 19:59.