Each operator with a dialing code
Now, at the time when everybody has at least two phone devices, operators had extended their businesses. Now, in a country, there are many operators and each one of them has different services. Each operator has a specific dialling code to be recognized by any user. If you forget to dial the dialing code, you cannot make the phone call. Each dialing code is number formed by four digits. When you choose your operator, you may choose also your phone number.