Help needed from SysAdmins

[Diya Saxena]

Hi 

Currently I am trying to communicate between two machines ( host-
target) via a serial null modem cable. But its always failing. I need 
all your help in setting up these. I will write down the queries below.

1. How to find out all the com ports that are available and the baud 
rate they support.

2. How to find out what baud rate my cable supports ( I got it from a 
pile of cables so no idea about that)

3. How to find out if my cable is working properly? Is there something 
like a ping command which can check the connection?

4. Looks like my system ( both host and target) has one COM port each. 
So should that be mentioned as /dev/ttyS0 or /dev/ttyS1?

Thanks a lot in advance
Diya