[A320] PTT Stuck and VHFx Emitting - explanation required
 

Hello,

Could anyone, please, explain the difference in the technical background behind the PTT STUCK and the VHFx (HFx) EMITTING procedures for A320?

The description for the both procedures starts with almost the same words; so what makes the FCOM and the ECAM process them as different faults and what makes them recognise one from the other? The only difference in FCOM is that there are time limits specified for the first one.

For example, say, 40 seconds have passed since the transmission on the VHF1 had been started, how does the system know if this is a 'PTT STUCK', a 'VHF1 EMITTING', or even a normal and arbitrary transmission?