Its overlay area code is the 289 area code. It was introduced to the public in the middle of 2001. The first Mississauga (Malton) area code was all used up in the later months of 2005, thus the 289 area code will become the area code of phone numbers that will be given starting from that time onwards.
Direct inward dialing (DID), also called direct dial-in (DDI) in Europe and Oceania, is a telecommunication service offered by telephone companies to subscribers who operate a private branch exchange (PBX) system.
Dialed Number Identification Service. Dialed Number Identification Service (DNIS) is a service sold by telecommunications companies to corporate clients that lets them determine which telephone number was dialed by a customer. This is useful in determining how to answer an inbound call. The telephone company sends a DNIS number to the client phone system during the call setup. The DNIS number is typically 4 to 10 digits in length. Any DID (Direct inward dial) number will have a DNIS. This is the number sent from the central office to the PBX (Private branch exchange) or key system, telling the telephone system which number was dialed.