This can be a problem with the software, or with the carriers. I am more inclined to say it is something with the software - but we will not see fixes until companies such as Telecom New Zealand and Vodafone New Zealand move.
I am trying to use my Apache Pocket Phone Edition and my i-mate Jasjar as modems for my tablet PC.
It won't work. I mean, the i-mate Jasjar will connect to UMTS for 15 minutes via Bluetooth and then just stop sending or receiving data. Nothing. The tablet PC is not even notified of the end of the data session. So I right-click the connection icon on my tablet PC and disconnect. Usually connecting again will do it. But it's every 15 minutes!
With the TNZ Apache I used the WMODEM program to connect via USB. Great idea, since it will keep the Apache charged, plus it is faster than the Bluetooth connection. Except that it works, well, only when it works. I am not sure it is a problem with Telecom's network, but for fours days now I was only able to connect twice using this method. The other times I tried (and I tried lots) the table PC stops at "Verifying username and password". And the WMODEM program on the Apache freezes, and a soft reset is the only solution to terminate it.
Then I tried Bluetooth DUN on the Apache. It shows the same signs as the i-mate Jasjar (so I think this is a problem with the OS), with no data traffic after 15 minutes. But on the Apache is worse: the entire unit freezes, and I need to soft reset it.
Ok, so who is gonna fix this? At least the Harrier had a patch soon after release to fix some Bluetooth problems - and it actually worked really well.