Glossary · DNIS
What is DNIS?
DNIS (Dialed Number Identification Service) is the telephony feature that tells the receiving system which number the caller dialed. When one phone system answers calls for many different numbers — a support line, a sales line, a toll-free number — DNIS is the signal that identifies which of those numbers was called, so the system can route, greet, and report on the call correctly.
How DNIS works
A single voice platform often terminates dozens or hundreds of numbers on the same trunks. Without DNIS, every call would look identical on arrival. DNIS solves that by passing the dialed digits along with the call in the signaling.
The receiving system reads the DNIS value and uses it as a routing key. A call to the toll-free sales number can open with a sales greeting and queue, while a call to the local support number opens with a support menu — all on the same underlying system, distinguished only by which number was dialed.
DNIS is especially important for toll-free and multi-campaign setups. A business running several marketing numbers can map each one to a different IVR flow and measure which campaign drove the call.
DNIS vs. ANI
DNIS and ANI are complementary, and easy to confuse. ANI identifies who is calling (the originating number); DNIS identifies what they dialed (the destination number).
| Aspect | DNIS | ANI |
|---|---|---|
| Answers the question | Which number was dialed? | Which number is calling? |
| Direction | Destination (called party) | Origin (calling party) |
| Common use | Route by line/campaign | Screen-pop, caller lookup |
| Example | Sales vs. support greeting | Match caller to a CRM record |
Together they let a system decide both how to greet a call (from DNIS) and what it already knows about the caller (from ANI).
Why DNIS matters for business phone
DNIS is the mechanism behind “one platform, many numbers.” It underpins campaign tracking, department routing, and clean reporting.
- Campaign attribution: assign a unique number to each ad, billboard, or landing page and use DNIS to see which drove calls.
- Department routing: send calls to the right queue based on the number dialed, without asking the caller to choose.
- Tailored greetings: play a different prompt per line so callers hear the right context immediately.
- Reporting clarity: segment volume, handle time, and outcomes by the number dialed.
DNIS frequently asked questions
What does DNIS stand for?
DNIS stands for Dialed Number Identification Service. It is the telephony feature that passes the dialed (destination) number to the receiving system so the system knows which of its numbers the caller reached.
What is the difference between DNIS and ANI?
DNIS identifies the number that was dialed (the destination), while ANI identifies the number that is calling (the origin). A call routing system typically uses DNIS to choose the greeting and queue, and ANI to look up the caller.
How is DNIS used in call routing?
The receiving system reads the DNIS value and treats it as a routing key. Each dialed number can map to its own IVR menu, queue, or greeting, so a single platform can serve many lines and campaigns while keeping each call in the right flow.
Is DNIS the same as a toll-free number?
No. A toll-free number is a phone number; DNIS is the signal that tells the receiving system which number was dialed. DNIS is commonly used with toll-free numbers because one platform often answers many of them at once.
See how DialPhone fits
DialPhone routes inbound calls with a drag-and-drop IVR and smart routing by intent, time, and menu on business phone and the contact center, so each number you run can have its own greeting and queue. For advanced ANI/DNIS-based routing rules, talk to our team about a call-flow design that fits your campaigns. Related terms: ANI, CNAM, and call disposition.