The advent of Direct Inward Dialing (DID) services provides people with access to local telephone numbers in most countries on a worldwide basis. These numbers are then forwarded by companies such as DID World Wide to PSTN (Plain Old Telephone System), VoIP or VoIM devices anywhere in the world. Essentially, this means that:
1. International and long distance telephone calls are made with the customer only paying local call rates.
2. You are able to add telephone numbers to your phone line so that you are no longer restricted to one telephone number per line.
3. Conventional telephone calls may be terminated at non-PSTN devices if desired, such as VoIP and GTalk. This has particular relevance for VoIP communications, as it allows people connected to the traditional PSTN network to call people connected to VoIP networks.
Over and above these basic functions of DIDs, there are many additional uses for local numbers. For example, consider the issue of privacy. If users place classified advertisements in a newspaper and they wish prospective buyers to contact them without publishing their own, private telephone number, a temporary local number could be provided by the newspaper.