Not sure if this is applicable to a Siemens phone, but do you have a CID set up for your connection to the Z? I know on Sony Ericsson phones you need to create a CID number under Data Comm. -] Data Accounts. In the event you are unfamiliar with a CID number, it\'s just a single digit that your phone creates to associate your phone to a data device.
I\'m on T-Mobile, and with my service if I want a reliable connection, I need to dial *99***2# where 2 is my CID. Without dialing that 2, things like ssh and Yahoo! mail don\'t work for me.
I also noticed on T-Mobile that if the connection is idle for about 1min it disconnects. Is your connection idle for roughly 30s or are you continually using it. It could be that the service in your area is just really bad.
T-Mobile was pretty good customer service. After I got to 2nd or 3rd tier data support, I was able to get someone who walked me through this set up process. Since then, I\'ve had really good luck using my SE Z600 to dialout to the internet.
HTH
Curt
