DID (Direct Inward Dialing) is a service provided by a local telephone company (or local exchange carrier) that supplies a block of telephone numbers for calling into another company's PBX system (private branch exchange). Using DID, a company can offer its customers individual phone numbers for each person or workstation within the company without requiring a physical line into the PBX for each possible connection.

DID's work this way: You have DID trunks which act as your incoming lines. You need DID extensions to work with the trunks. You have a lot more phone numbers than you do lines. For example, Company A has 4 DID trunks and 100 DID extensions. You can have approximately eight incoming calls per trunk. Once a trunk has been maxed out, the other incoming calls will spillover onto the next available trunk. Assign the numbers to each person who needs a private telephone line, then assign numbers to each person who needs a fax number. Assign a block to your sales department or to your administration department - you decide how you want the lines allocated and there are endless variations.

As a result, an incoming call will come in, the central office then sends the last three or four digits of the dialed number through the first available trunk. Your DID compliant computer telephony board or PBX circuit card detects those dialed digits and passes those numbers to the application software which then uses that information to route that incoming call. A DID system can be used for fax, voicmail, as well as for live voice connections. Compared to regular PBX service, DID saves the cost of a switchboard operator, calls go through faster, and callers feel they are calling a person rather than a company.

As an authorized network distributor of Bell Canada, Telanet Canada Inc. can provide you with more information on DID systems and offer you solutions to suit your business needs.

For more information, please e-mail us at sales@telanet.com