Direct Inbound Dialing

It is a feature offered by the companies for the use with their customers PBX (Private Branch Exchange) system. A DID company can allow company to assign a personal number to every employee, without any requirement of separate physical phone line to connect to the PBX. By this way, telephone traffic can be managed more easily.

Let’s clear your doubts with an example.

Suppose, if an organization has 25 employees and every employee has a separate telephone number within its physical location the organization can rent 10physical trunk lines from the telephone company which allows 10 phone calls to take simultaneously. The rest people have to wait till they are getting line free. And rest other people will be hearing busy signal or voice mail system.

One Key information: A DID system doesn't require PBX operator and also can be used for Fax and Voice Termination.

Compared to regular PBX service, DID saves cost of switchboard operator, and caller feels that they are calling a person instead of the company.

DID also works for VoIP communications. To allow PSTN users to directly reach VoIP users, DID numbers are assigned to a gateway. This Gateway connects with Public Switched Telephone Network (PSTN) to the VoIP network, routing and translating calls between the two networks for the VoIP user. Calls from the PSTN will be directed to the VoIP user who holds the corresponding DID number.

When any callers call a person in a company through public telephone number, calls are received by the end office switch in public telephone company where the public telephone operator connects call to available incoming trunk lines between the telephone company switch and PBX Switch.

Calls originating in VoIP network appear to users on PSTN as originating from the assigned direct inward dialing numbers.