I have this Ericsson F121s unit
http://www.cpg.com.tr/downloads/fct_f121s.pdf with SIM card inside. The unit and SIM card was supplied by Cesky Telecom for customers in place, where there weren't fixed line cables to provide them with Cesky Telecom services. It works like normal Prague residential phone and has assigned Prague( not mobile) phone number. Otherwise it uses on Eurotel GSM network. What I did, I tried to use the SIM card in other mobile phones, but it still asked for SIM code. When I did returned SIM card back to original unit, it has registered with network immediately. No PIN codes typed in. Do you have any idea how to get SIM code from the Ericsson F121s unit? Any advice welcomed.
Thanks Lukas
P.S. The other option is that SIM card is assigned to IMEI code.