4. Receiving a call

The previous page described making a call which gets as far as the mobile switching centre and the telephone exchange

If it is a mobile-to-mobile call then eventually a call request is received by a mobile switching centre. This may or may not be the one that started the call.

Each base station controller keeps a log of all the mobiles it is currently connected to. This data is fed into a master database held in the mobile switching centre. So the call request is checked against the database - if the number is active, then it is routed to the relevant base station controller and eventually to the phone itself.

All this takes less than a second to accomplish.