To answer some questions:
Q: If ZC files are sound files, what is the difference between them and other sound file types such as WAV or MP3?
A: ZC files are generally much smaller, and therefore use less resources. There is no advantage in converting them to WAV.or MP3.
Q: Can you send a zc file or to to firstname.lastname@example.org?
A: Yes will do.
Q: Can common computers can play ultrasound, and if so can people here it?
A: Yes. Virtually all non specialist computers can play ultra sound, but PCs built prior to 1984 may have problems obtaining software. Virtually all Android, iOS, and Windows phones can as well. Most bat call analysts don’t listen to ultra sound, they look at it! But it’s easy to listen to if you want, just slow down the playback.
Q; Is a zero crossing file is really a recording?
A: Yes! Anything that is recorded is a recording!
Q: Is zerocrossing (ZC) a smaller file that captures only some specific information related to bat calls?
A: Yes. Its small file size is one of it’s greatest advantages, leading to big cost savings, and is why many researchers and armatures chose it over WAV.
Q: The only way for anyone to use that file to confirm the ID is by downloading it and analysing it in certain software. Seems to be a very different thing from the photos and recordings iNat currently supports?
A: Not at all. To view photos on a PC you need to install software for viewing photos (or have someone do it for you). To view ZC files you need to install software for viewing ZC files (or have someone do it for you). See! No difference, its exactly the same! No data of any type can be viewed on a computer until you (or someone) installs software to view it. If you don’t do that, you can only look at blank screen. If you are looking at this page now, it’s because you (or someone) Installed software on your computer for viewing web pages.