I just found that if you press the down button when the t680 is showing the "Connecting to " dialog, you get more infos:
Instead of showing
"initializing"
"connecting to ..."
"signing on"
"connected"

it will show more detailed information
"Initializing"
"connecting to ... + phone number"
"connected 300"
"signing on ... negotiating"
"connected"

It might be useful if something does not work...