Is it possible for a network to get an N900's IMEI if the device doesn't have a SIM installed? I know some sources (such as Michal Jerz's superb preview) suggest the GSM radio is off when no SIM is there, but most GSM phones have to able to make an emergency call even if there's no SIM. I wondered if those who understand how Fremantle handles telephony could shed some light on this.

Can you describe the usecase? How do you want to access this and why? From code of another app? Or just because you're curious?

It's from a security PoV. There are people who may wish to travel to areas where they do not want the network to see the IMEI and hence recognise the origin of the device, but would like to be able to use the computing power or use wifi on a secure network.

I still don't know what you mean by "network" here. If you don't have a SIM card inserted you can't use GSM/... I assume.
So your question is whether the IMEI can get asked for in a WiFi?
I still don't totally get the usecase but maybe I miss enough knowledge.

you stil can turn off the gsm radio, and in that case no gsm communication should occur at all (thus no imei retrieval either)...

Sorry if I'm not making myself clear... There is at least one case when the GSM network will accept a call from a device without a SIM. I was wondering whether that meant the device declared itself to the GSM network, thus giving its IMEI, when powered up or only when attempting to make the emergency call.

@andree: Thanks for that. Am I right in assuming that if there's no SIM, the GSM radio's off by default? Is that documented somewhere?

My guess would be that the N900 will behave like any other Nokia phone in this matter (like the s60 devices).. So whatever the S60 device does in the "Offline" mode.. I think the N900 will do the same..

Yep, and don't forget to put your tinfoil hat while you're at it

Just kidding, of course - it's a valid question for the privacy-concerned.

From what I have seen, networks seldom use the device IMEI for subscriber identification opting instead for the SIM cards IMSI or an electronic serial number.

Towers though do log traffic using the IMEI... So yes, the N900 should be capable of making "emergency" calls without a SIM and the tower it uses to connect to the system could also record the device IMEI.

I still don't understand this "security POV". Are you asking; when the N900's radios are off and no SIM is inserted will it still transmit its IMEI to the nearest tower?

EDIT: I see that you clarified you question while I was preparing a response.

Also helpful >> http://nds1.nokia.com/files/support/...-US_es-LAM.pdf

i believe most phones without sim stay unregistered unless you try to nake an emergency call.