AAAhhhh.... so you found that foreign site too eh?
I believe bsy is the busy channel lockout, keeps you from transmitting over someone else when you are using tone coded squelch
I am going to guess SHFT is shift what it does, I have no idea....
If you are looking at 2107's off ebay keep in mind those radio's more than likely don't have any fcc or industry canada approval. As a rough translation, you won't find a radio shop in north america that will work on them.
I have one of the tk-2207 and I love it. I take it on fire calls so I don't abuse my tk-2170. I have dropped it in 12" of water a few times and knocked it of my pocket while running in to the station several times. With all that it still works great. The only thing I did not like is it is not capable of doing two tone.