why do we need SIM cards

johnnybravo55

a few yearsago i was holiday in Venezuela and they still use analogue mobiles and don't use sim cards.. when you buy a mobile you buy a type of contract with all the networks and during the day if you get poor service you just change networks on your phone. so these networks have to provide the best service or lose business. they wont use digital mobiles cos digital mobiles cn be traced by secret services.. also a 20 minute call in caracas cost only 0.000 why so cheaper than us?1p

esuhl

As far as I know, there's nothing in either analogue or digital mobile phones that could be associated with an account. The main purpose of a SIM card is to identify the user (hence the name Subscriber Identity Module) for billing purposes.

If users don't have a SIM card, how do the networks identify them? And if all local network operators allow the user to access their service, where is the account set up? Does the user receive a bill from every network operator every month?

As for digital mobiles being "traced by secret services"... any muppet with an analogue radio scanner can listen in to an analogue mobile phone conversation. Digital transmissions are at least encrypted.

Finally... why would the network need to "provide the best service or lose business", when you say that a 20 minute call in Caracas costs 0.000 random currency units? They clearly can't make a profit anyway.