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What is Direct Inward Dialing (DID)?

|  3 min
History of VoIP
In this article

Direct Inward Dialing is a technology developed to provide a block of telephone numbers for a company’s PBX (private branch exchange). Those numbers are available for distribution to a host of different individuals or departments without each needing a separate incoming phone line. In its original analogue form, it was first offered around 1960 by companies such as AT&T but required the installation of costly hardware in the customer’s premises. 

At one time, the wider telecom infrastructure that was required was also expensive. Incumbent local exchange carriers (ILEC) were set up to deliver the loops and other facilities required but the infrastructure was only affordable for the largest corporations. Similar operations called competitive local exchange carriers (CLEC) were supposed to widen availability by leasing capacity in a competitive market but had limited success. 

The advent of VoIP and wholesale DID origination is now bringing all those benefits at a far more affordable price and without the need for elaborate physical hardware on site. A DID provider, such as IDT Express, aggregates access to the variety of resources needed to make those connections for you. Calls made to that number are then forwarded to your VoIP, usually using SIP (session initiation) protocol. 

The advantages of wholesale DID origination

Your virtual numbers can be local to you or a local number in any city of the world, enabling you to have a “local” presence everywhere. This is far more appealing for customers in those locations. Since each extension number can be linked to a regular or mobile phone located anywhere, this also means your workforce can be distributed in a variety of diverse locations or even working from home. 

What is Direct Inward Dialing Appear Local

In addition, you have all the other benefits of internet-based telecommunications, such as easy extensibility, instant control of forwarding, blocking and filtering, and integration with CRM software and voice recognition systems, transcription, recording and archiving. Because they are carried by SIP, your network of connections can also be used to carry video calls or fax messages. 

Significant financial advantages of DID

Not least, of course, all these opportunities can be realised without requiring costly hardware or trained operators. Now that your key personnel and different departments can be reached directly by incoming callers (at all times, even if their location varies or they are in transit), you have also relieved your receptionists of a great deal of telephone answering and message forwarding duties. In fact, the receptionist is only needed if the caller still requires assistance to identify the correct office. Alternatively, an automated system can help callers find the desk they need. 

Even more important, there are also productivity improvements in the form of increased customer conversion. With traditional telephone lines, if the number was engaged or there was a queue of calls, the customer would simply give up and call someone else. If your phone line is a sales artery for your business, you simply can’t afford to drop calls or tolerate delays in connecting your callers to your personnel. 

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