Terminal servers hang when loghost hangs

We have three Digi PortServer CM 32. Our console loghost for these three portservers is connected to one of these three portservers. When our console loghost hung last week, all of the ports in the three portservers were inaccessible. When we powered cycle the console loghost and rebooted the portserver where this console loghost is connected to, all of the ports in all the portservers became accessible. Why did the portservers get affected when the console loghost hung? Is there any workaround so we can prevent this from happening (aside from keeping the console loghost more stable)?

What version of firmware is in this unit?

Here it is:

#more /proc/version
Linux version 2.2.14 (root@cm.digi.com) (gcc version 2.95.2 19991030 (2.95.3 prerelease/franzo)) #4 Thu Nov 14 15:02:42 PST 2002
Digi–CM 32 --Linux V_1.3.4g (Nov/14/02)