I'd guess the radio interface will emit DBus signals on status changes, if this is the case then it's relatively simple, make a program that listens for those signals and then does the network connect/disconnect accordingly.

icd_dbus_test.py has some python code for talking with ICD (note: it's my personal test script so it might do different things from time to time), see also http://www.qaiku.com/go/56ho for enabling eavesdropping on the DBus (for reverse-engineering stuff that either is not documented or is documented wrong...)

add me to the list too. I was a long time E90 users and was never faced with this problem but i have had it with different phones with the same operator. I have been doing some testing I have activated the data and setup a continuous ping with a larger packets and left it running, also i have have launched the browser and gave it a big webpage to load with a lot of flash.

3G data connection is still activated and calls go through the odd one got rejected probably as I wasn't giving the phone a break lol.

I then force the phone to use 2G and with the same results

All below had problems.
Tmobile
Vodafone
o2

I did this about 10 times on each network. A few times data disconnected red cross and the phone rung. Other times straight through to voicemail. There has to be something setup or a fix for this as this is becoming a deal breaker for me as much as I love the phone not all my locations I am in have good reception.

This isn't even possible on the N900 yet.

So this is why people suddenly stopped calling me:P Haha, I had realized that if i had an active data session I was unable to recieve calls, however SMS seemed to work.
I mostly use GPRS to conserve battery, it's really unneccessary with 3G for IM's and small quantities of surfing. But if I always use 3G people will be able to call me?
I will need to experiment on this, and see if the battery time will be acceptable.

I had a similar issue on my n900 here in the UK and im on the 02 network. This occurred last week, I had my 3G switched on and was signed into msn via the conversations plug-in. that is all i had on. I drove over to mate house an i tried makin a call but kept coming up "call could not be established" error. I tried calling diff ppl but same result. As soon as i disconnected the 3G web, it was working fine!
Anyone know why this happens or any way to fix it........??

Hi,

Have anyone experience not receiving calls on your N900 despite the callers claiming they called?

This has happened to me a lot, ppl have been asking why i am not answering calls all the time. But the problem is, my N900 is not even showing any calls coming in. I have tried calling myself from another phone as well and witnessed this myself. Very often a reboot would fixed it but not for long before it happens again.

I have contacted my service provider and they have sent me a new SIM card but the issue is still happening.

Can someone shed some light on this?
Thank you

This will happen if you are using EDGE -- connected and using the data. While using the data on EDGE, voice will not go through (sometimes). Only 3G will allow simultaneous data and voice.

I am not sure what EDGE is? but my internet connection is active on my N900.
Should i disable that?

Do you see "3G" or "3.5G" under your signal bars? If you see something other than those two AND you are using data (internet), then that is the reason why the calls are not going through. What do you have, T-Mobile or AT&T or another service?

I am on AT&T, under the signal bars it is showing 2.5