Tracking SIM and handset
http://news.bbc.co.uk/2/hi/technology/4738219.stm
IMSI number:standing for International Mobile Subscriber Identity
IMEI(number):International Mobile Equipment Identity
IMSI-catcher:tricks the phone into routing its call via the IMSI-catcher where it can be passed on for decryption.Once received, the IMSI-catcher passes the call on to the network, so the suspect is none the wiser he is being monitored.
