| Ah! Thanks for correcting me.   So to answer the OP: Install hamchat on kp4rv-3 On one computer, connected to any node, go to the stated address with your browser.  Enter a callsign.   On the second computer, connected to any node, also go to the same link and enter a callsign.   Type a message on either computer and hit "enter" and it appears on both computers.  Repeat.  
 
 
 
 [vk2iuw 2015-08-03- 15:41:41]: Link should be:
http://kp4rv-3:8080/cgi-bin/hamchat.pl |