Glossary
Direct Inward Dialing (DID)
Definition, how it works, and why it matters for service businesses.
Direct Inward Dialing is a carrier feature that lets a business own a block of individual phone numbers that all funnel into the same underlying trunk or system, so each number can be routed to a specific extension, crew, or service line without a human manually patching calls through.
How it works
A carrier assigns a range of DID numbers tied to one physical or virtual trunk; when a call arrives on a particular number, the phone system reads which DID was dialed and routes it accordingly — different numbers can map to different marketing campaigns, service lines, or locations, all landing in the same underlying system.
Why it matters for service businesses
Trades businesses that run separate residential and commercial lines, operate in multiple locations, or track different ad campaigns use DIDs to know instantly which line a call came in on, without the caller having to do anything different or the business needing separate phone hardware for each.
Example
An HVAC company prints one number on its Google ads and a different number on its truck decals; both are DIDs feeding into the same AI receptionist, which greets each caller appropriately and tags the lead source for reporting.
Related terms
- Virtual NumberA phone number that is not tied to a specific physical phone line or location. Virtual numbers can be routed anywhere, allowing businesses to have local presence in multiple areas without physical offices.
- Call RoutingThe process of directing incoming calls to specific destinations based on predefined rules. These rules can be based on time of day, caller ID, menu selections, or caller intent detected by AI systems.
- Business Hours RoutingA call routing feature that directs incoming calls differently based on whether the business is open or closed. During business hours, calls may go directly to staff, while after-hours calls can be routed to an answering service or voicemail.
- Call AnalyticsThe collection and analysis of data from phone calls, including call volume, duration, peak times, caller demographics, and outcomes. Service businesses use call analytics to optimize staffing, marketing, and customer service strategies.
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