A confession

I don’t really understand the technology behind Push to Talk–that walkie-talkie function that used to be exclusive to Nextel but now almost everybody has–nor do I understand the practical difference between it and standard cell phone use.

I mean, what’s the difference between PTT and a regular call on speakerphone? In what ways is it superior, and in what ways is it inferior? Just from the context and the ways I’ve seen it used, it seems sort of like AM vs. FM–PTT is more reliable but lower in sound quality–but I don’t really know if that’s even true.

Can anybody out there help me out here?