Cause: There is an incompatibility in the PHY chips being used between these switches - this has been fixed in software but also requires the ports to be set to 1000FD for the SFP/GIG link to pass traffic

1)  2816 SFP Plus - 3C16485 to connect the gig sfp port to a 2848 SFP Plus (3C16486)

Use version 1.0.1.0 for the 2816 SFP Plus (3C16485) – this is already on the web page under www.3com.com – set the SFP/GIG port you are using to 1000FD.

 Load software file “2848.V.1.0.2.6” on the 2848 SFP Plus (3C16486) and set the GIG/SFP port to 1000FD 

Note: The above is only needed when connecting these two switches together via the SFP port – when connecting them to any other switch you can leave the GIG/SFP port  set to AUTO.

2) 2816A SFP Plus (3C16485A) / 2824 SFP Plus (3C16487) – to connect the GIG SFP port to a 2848 SFP Plus (3C16486) –.

Load software file “ES2824.V.1.0.1.1.bin”  (will also be on the web page www.3com.com ) on the 2816A (3C16485A) or 2824 (3C16487) and set the port speed to 1000FD  - after loading the code and setting the speed it may  require you to also disconnect/reconnect the sfp port or reboot the switch.

Note: if running version 1.0.0.4 or earlier on the 2816A  - you must upgrade to version 1.0.0.11 first before upgrading to 1.0.1.1 – The reason for this is the way the EEPROM was formatted in the earlier versions of code  - If this is not done then your configuration may not be saved after a power cycle 

Load software “2848.V.1.0.2.6.bin  (will also be on the web page www.3com.com ) on the 2848 (3C16486) and set the port speed to 1000FD 

Note: The above is only needed when connecting these two switches together via the SFP port – when connecting them to any other switch you can leave the GIG/SFP port  set to AUTO