Posted:	 8/11/1998
Updated: 9/10/1998

        We have recently verified that the SuperStack II Switch 3900 contains a 
hardware bug which in certain environments and under certain conditions can 
cause an individual 10/100 port to stop forwarding data.  The frequency 
of occurrence is very small, no data is corrupted  and failure to forward data 
is limited to individual ports.  The bug occurrence is related to environmental 
factors including noise on the line in combination with the configurations below:

-       Ports operating in 10 Mbps half duplex
-       Ports wired using stand-alone media converters
-       Ports connected to some non-3Com end-station network adapters cards

        Ports experiencing the problem can be recovered by moving the 
connection to an unused port on the Switch 3900, this will restore service to a 
particular line since other ports on the Switch 3900 remain unaffected.  
Alternatively, rebooting the Switch 3900 will restore communication on any 
failed ports.  

         We have definitively analyzed and corrected the problem and have 
introduced the solution into our  volume production line.  3Com will offer a
replacement for all units which have exhibited this failure condition.  
Customers that have experienced this problem should call their local CSO 
Customer Service representative to arrange for a unit replacement.