Direct Inward Dialing/Direct Outward Dialing (DID/DOD)

Direct Inward Dialing (DID) is a service of a local phone company (or local exchange carrier) that provides a block of telephone numbers for calling into a company's private branch exchange (PBX) system. 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.

Direct Outward Dialing (DOD) is a service of a local phone company (or local exchange carrier) that allows subscribers within a company's private branch exchange (PBX) system to connect to outside lines directly. Using DOD, a company can offer each person or workstation within the company the ability to dial numbers direct, without the need to go through an operator or dial other numbers first.

DID and DOD is often used together.

References for the glossary can be viewed by clicking here.