The first step is to follow the network setup guides on the 640H support page. Once you have completed the setup, you need to 'ping' the 640H (this is explained in the guide).
If you can ping the unit the network connection is intact, as this shows that the unit can recieve data and send data, showing that the hardware in the unit is fine, as is the hardware in your network. Also, the 640H has been enabled to send and receive all inbound and outbound TCP and UDP communications so the problem is not within the 640H itself.
The likely areas to address are router and firewall settings. On the 640H, is the name server and gateway set to the correct IP address? Usually, this is your router.
You may need to add the IP address of the 640H to your router permissions table to allow the communications through.
If you cannot ping the unit, refer to section 3.2 of the Network Setup guide for details on how to set the network connections and settings on your computer.
If you can ping the unit, then you need to address your firewall and router settings, as the 640H is functioning correctly, and the error lies elsewhere.
Due to the large number of routers and firewall programmes available, we are unable to provide assistance on specific routers or other programmes on your computer, and we would advise that you discuss this with your computer dealer or service engineer.
If you have recently updated your version of Mac OS 10.4 to the latest release, Apple have changed their SMB preventing embedded systems accessing it. The solution to this problem is to download and use the sharepoints software as we suggested in the network guide.