I’m trying to decide what system to buy, and have some questions about exactly how they work.

If I have an intercom system with audio in I’m assuming I can run any device into that IE a phone, ipod, etc…some advertise a scanner audio input

Q#1: Can I hook any audio device even to a scanner input?

Q#2: Does the intercom system automatically stop the audio in when you speak? (interupt the music) or do you have to push the PTT for that?

I want to have an intercom/radio vhf system…

Q#3: In the case does the PTT only work for radio communications?

Q#4: What is my best "Bang for the buck" package out there for a intercom/radio system?

I may only buy 2 headsets to start, but I need it expandable to 4