Using the Ericsson R380 on Orange?

[Guest sponge]

I bought a £1 Orange PAYG SIM card so I can get their 2-for-1 cinema tickets and intended to use it in an old R380 that I got off my Mother-in-law. I've put it in and it's saying Emergency Calls Only. I expect this is due to my not registering the SIM card yet. However, the instructions with the pack state I need to supply Orange with the phone's IMEI number and this got me thinking.

Is the IMEI used just the once, for '1st contact'? Can the SIM then be used in any other (unlocked) phone? It's just that I don't even know if this R380 is locked or can be used on the Orange Network or not. I don't want to tie it to this IMEI number (the R380), find out I can't even use the SIM in the phone as it's locked, and then not be able to use it in another phone which isn't???

I not 100% on the process and hope someone can advise. Thanks in advance.

Edited November 21, 2006 by sponge