Linux stuck when serial cable is disconnected

[hagit <hagit_guy@hotmail.com>]

Hi all,
I am running on a MIPS machine, with my kernel and debian distribution
(file system).
The kernel messages are configured to get out from the serial
connection, i.e. serial console.
When the serial output of my MIPS is connected to my PC everything is
OK and I can see the outputs in the terminal.
When I disconnect the serial cable my Linux get stuck. Even my telnet
connection doesnt responds.
When I re-connect the serial everything is OK again.
Do you know what can be the problem?
I am working with HW flow control? can it be the problem?

Thanks a lot!
Hagit