Local calls within the same area code can be completed by dialing only the 7-digit number. Callers who do not dial the proper number will hear a recording announcing the change. Once Mandatory Dialing starts, callers are required to dial the 10-digit number on all calls. Callers who do not dial the proper number will hear a recording announcing the change. Ten-digit dialing is necessary when calling another area code or when making a toll call.
Area codes have a geographic identity.
People can get an idea of where a business or individual is located by looking at their area code. Each time there is a geographic split, businesses have to pay to reprint all of their literature, promotional items, stationery and business cards to include the new number. Geographic splits are not long-term solutions and future area code relief must be undertaken. For example, the Chicago metro area used to be served by just the 312 area code. Only new customers or businesses or individuals requesting new lines get the new area code.