[ale] How do I reset user timeout in ubuntu?

[Jim]

If I log into a remote ubuntu system via ssh, and leave the session idle 
for a while, I get disconnected.  The disconnect first becomes a dead 
session.  Meaning I can not type anything into the session.  Keys don't 
work and output obviously doesn't come back.  After a much longer period 
of time, I get a "disconnect by remote" message.  timeoutd is not 
running on the system.  I looked in sshd_conf for something relevant, 
but no luck.  This only happens on this system and there are no messages 
in syslog/message/auth. 

Can anyone suggest where the timeout is occurring?

Thanks,
Jim.