Dialed number identification service (DNIS) is the information a phone carrier passes to your phone system that says which number the caller dialed. When a business has several numbers ringing into the same system, such as a sales line, a support line, a toll-free number and campaign numbers, DNIS lets the system tell them apart and handle each one differently: a different greeting, menu, queue, script or report. The term comes from older contact center and toll-free services, but the same idea is built into modern SIP trunking, cloud phone systems and contact center platforms.
At a glance
- DNIS identifies the number the caller dialed, not who is calling; the caller’s number is ANI.
- It lets one phone system or contact center route, greet and report on each of your numbers separately.
- In SIP-based services the dialed number travels in the call signaling and is normally included with each call.
- Common uses are campaign tracking, separate brands or product lines, language lines and franchise or location routing.
- Its value depends on your platform passing the dialed number through to menus, agent screens, CRM and reports.
What problem it solves
Many businesses publish more than one phone number, but they don’t want a separate team or phone system for each. A bank might advertise one number for credit cards and another for mortgages that both ring into the same contact center; a marketing team might put a different number on each campaign; a company with several brands might share one service team. Without knowing which number was dialed, every call looks the same, so callers hear a generic greeting, sit through extra menu steps and are often transferred.
DNIS solves this by telling the system which number the call came in on. The interactive voice response (IVR) or automatic call distributor (ACD) can then play the right greeting, skip unnecessary menus, send the call to the right queue and show the agent which line or campaign it relates to. It also gives marketing a simple way to count calls per number.
How it works
Numbers. The business holds a set of numbers, such as local direct inward dialing (DID) numbers and toll-free numbers, all pointed at the same trunk, phone system or contact center.
Delivery with the call. When someone calls, the carrier passes the dialed number along with the call. On SIP trunks it is carried in the call signaling, typically in the request address and the “To” header; on older digital circuits such as PRI, the carrier sent the dialed digits, often the last few, when the call was set up. For toll-free numbers, many services deliver the toll-free number the caller dialed, but check, because some configurations pass a different routing number instead.
Routing rules. The PBX, cloud phone system or contact center platform matches the dialed number to a rule: which greeting or menu to play, which queue to use, which business hours apply and what data to show the agent.
Reporting. Call records store the dialed number, so reports can show volume, wait times and outcomes per number, per campaign or per brand.
Forwarded calls are the common catch. If a call is forwarded from another number or carrier before it reaches you, your system may receive the forwarding number rather than the number originally dialed, depending on how the forwarding is set up.
When it matters for buyers
- When several numbers share one team. Separate brands, products, languages or regions can share agents while still getting their own greetings and routing.
- When you run call-based marketing. Unique numbers per campaign, read through DNIS, are the simplest form of call attribution.
- When you move to a new phone or contact center platform. Routing that depends on dialed numbers has to be rebuilt and tested, and every number has to be ported or re-pointed.
- When you consolidate locations or acquire a business. Inherited numbers can keep their own identity on a shared system.
Questions to ask vendors
- Is the full dialed number delivered on every call, including toll-free and ported numbers?
- How many dialed numbers can we route separately, and is there a per-number charge?
- Can the dialed number be shown on the agent’s screen and passed to our CRM and reports?
- How are forwarded calls handled: will we see the original number dialed or the forwarding number?
- Can we change routing for a number ourselves, and how quickly does a change take effect?
- During migration, how will you test routing for every number before cutover?
How it differs from ANI
Automatic number identification (ANI) identifies the caller: the number the call is coming from, used for billing, routing, emergency calls and customer lookup. DNIS identifies the destination: which of your numbers the caller dialed. They answer different questions, so contact centers often use both together. ANI might pull up the customer’s account while DNIS tells the system the caller rang the mortgage line rather than the credit card line. Caller ID is different again: it is the number and name displayed to the person receiving a call, which may or may not match the ANI.
Problems this helps with
- Several phone numbers ring into one team and agents don't know which one the caller used
- Can't tell which ad or campaign number generated a call
- Calls for different brands or languages all get the same greeting
