An A320 comms question

[AF330]

Good morning,

Sorry for talking back this very old thread...I had some questions related to comms as well.

On this thread, we said that to answer an attendant call --- Press the RESET key, select ATT transmission key, release and rotate the CAB reception knob (to be able to hear the attendant) and either use the RAD PTT, sidestick PTT or hand mike PTT keys to talk.

1. So what is the use of these transmission keys? Do they just enable transmission from the cockpit?

2. Let's say I have tuned VHF1 on RMP1. VHF1 Transmission key is selected on ACP (3 green lights on). I have pulled and rotated the VHF 1 knob on ACP as well. I can now contact ATC using three ways:
- Use the RAD spring loaded switch
- Use the hand mike PTT
- side-stick PTT.

Now, let's say we receive a call from cabin crew. The CALL light turns amber. We press the RESET key and push the ATT Transmission key. We then pull and turn the ATT reception knob. We can now transmit and receive to/from the cabin crew. We can transmit using three ways:
- Rad PTT
- Hand mike PTT
- Side Stick PTT

We notice here that we transmit using same methods. However, when pilots talk to cabin crew, they don't transmit to ATC (hopefully!). So what happens exactly? VHF 1 Transmission key automatically turns OFF to let us transmit to cabin crew?

3) If ground contacts us, MECH turns amber. We reset the switch. We now have two ways to talk to each other:
- INT
- Press the transmission key (VHF 1 transmission key which was selected before turns OFF) + a PTT switch (RAD/Side Stick/Hand mike)
Is this right?

4) I had the chance to get a small ride in the cockpit few months ago (jumpseat). Pilots gave me a headset (connected to RMP/ACP 3) and I could hear both pilots. However, they could not hear me when I would talk. What configuration was this? How do pilots talk between them during flight? They keep the position on INT? So on ground, they keep it on Normal and as soon as ground disconnects, they pass it to INT?

Thanks!