The is there to grab the serial card's attention. Without it, it won't know how to respond.

I'm suggesting the ZTerm thing to see if you have the right cabling because there are various types of serial cable. I don't think that hardware handshaking is important in this case, so the only thing that's going to matter is whether you have a modem cable or a null modem cable. The two pretty much look the same (well, as similar as any two serial cables can look -- which is not very!), but there are a few pins switched around.