What is a DID(Direct Inward Dialing)?

Allowing extenal callers to contact a particular extension directly.

Being in business means you will often need to communicate with specific individuals within different companies. However, directly reaching these people can be challenging as you need to go through a receptionist. While this might be acceptable initially, it can become frustrating over time. Similarly, customers may feel upset when they have to wait for long time.

To avoid making customers feel neglected and ensure timely help, investing in a Direct Inward Dialing (DID) service is worth considering.

What is a DID?

A DID, or Direct Inward Dialing, is a telephony feature that allows individuals or businesses to set up virtual numbers for incoming calls. Nowadays, most VoIP phone systems and PBX (Private Branch Exchange) systems offer this functionality.

What Is a DID Number?

With a DID number, callers can directly reach a specific extension or device within an organization, bypassing the need for a receptionist or switchboard. Businesses can assign unique numbers to different destinations instead of using traditional phone numbers tied to specific lines.

DIDs are commonly used in business phone systems to streamline incoming calls and facilitate efficient call routing. Companies purchase DID numbers from telecom companies or service providers and allocate them to internal extensions.

Types of Direct Inward Dialing Numbers

Depending on your business requirements, there are various types of DID numbers available:

Local DIDs: These numbers are associated with specific geographic regions or cities, allowing businesses to establish a local presence and receive calls from customers in those areas.

Toll-Free DIDs: Enable customers to call without incurring charges. Commonly used for customer support or sales hotlines, these numbers typically start with prefixes like 800, 888, 877, or 866.

International DIDs: These numbers are assigned to specific countries or regions. They allow businesses to have a local presence in different countries and receive calls from international customers.

Vanity DIDs: Customized phone numbers that spell out a word or phrase using alphanumeric characters. For example, a business might choose a vanity DID like “1-YEASTAR” to make their number more brandable.

Mobile DIDs: Associated with mobile devices, they are ideal for businesses requiring mobility or a dedicated mobile line.

How does Direct Inward Dialing work?

DID can work in one of two ways – through a Public Switched Telephone Network (PSTN) or a VoIP phone system.

how direct inward dialing works

Direct Dialing on PSTN

In the PSTN way, the Direct Inward Dialing works by Private Branch Exchange (PBX).

When using PBX, the DID provider allocates trunk lines to the customer’s phone system. Then, they allocate several telephone numbers to those trunk lines. The numbers are assigned to customers and act as their direct-inward-dial numbers. When people make inbound calls, the DID phone number is transmitted and routed to the right person.

Recently, many phone services provide Direct Inward Dialing via PRI circuits. However, if you don’t have enough lines, the next caller will hear a busy signal and have to wait until a line frees up.


When it comes to DID and VoIP users, it is even easier to use and manage, mainly due to the SIP trunking. The trunk lines connections are not actual physical lines – instead, they are virtual, and the phone numbers are linked to all the extensions your business uses via software.

This solution is a lot more convenient than using PSTN, as you don’t have to rely on a telephone company to take care of the hardware installation.

What are the benefits of  VoIP DID?

Reduced Costs


Increased Flexibility


Better Customer Service


Enhanced Team Collaboration


Local Presence


Agents anwering calls after interactive voice response route the caller to the agent

What is Direct Inward Dialing used for?

Lead Generation Tracking


DIDs allow sales team to track the performance of specific numbers, enabling better analysis and improvement.

Efficient Customer Service


Customer support departments can set up DIDs for different purposes like billing questions, technical support, or general inquiries. By having dedicated numbers, calls can be routed more efficiently to the appropriate team or agent, resulting in quicker and more effective customer

Multiple Location Integration


Organizations with multiple locations can set up a DID for each office. This facilitates seamless transfers between branches and ensures smooth internal communication within the company.

Marketing Campaigns


Marketing teams make use of unique and temporary DIDs for specific advertising campaigns or events. Assigning a specific DID helps them gauge response rates accurately and assess the success of their marketing initiatives.

Direct Inward Dialing(DID) – Common FAQs

DID vs DOD: What is the difference?


DID (Direct Inward Dialing):

  • Inbound Calls: DID is primarily focused on handling inbound calls to an organization.
  • Assigning Direct Numbers: With DID, a range of phone numbers is assigned to a company’s PBX (Private Branch Exchange) system.
    These numbers can be directly dialed by external callers to reach specific extensions or departments within the organization.
  • Call Routing: When an inbound call is received, the call is routed through the PBX system and directed to the appropriate recipient based on the dialed number.

DOD (Direct Outward Dialing):

  • Outbound Calls: DOD, unlike DID, is concerned with facilitating outbound calls made by employees or users within an organization.
  • External Dialing: DOD enables individuals to directly dial external numbers (outside the organization) without going through a receptionist or operator.
  • Access to External Lines: DOD allows users to access external lines directly from their telephones or other communication devices, bypassing any internal routing or restrictions.

In summary, DID assigns direct numbers to extensions or departments for managing incoming calls, while DOD enables users to make outbound calls directly without intermediaries. Both features enhance communication efficiency internally and externally.

How do I get a Direct Dial-in?


How to set up DID on Yeastar phone system?


Configuring inbound routes on the Yeastar PBX System to route calls based on DID telephony is easy and no need to pay extra money. And all editions of Yeastar phone system support this feature.

For a detailed step-by-step guide, please refer to the video and links provided below.

Can I have multiple DID numbers?


Yes, you can have multiple DID numbers.

In fact, having multiple DID numbers is a common practice for businesses that require separate phone numbers for different purposes. Each DID number can be associated with a specific department, employee, geographic location, or function within your organization.

Having multiple DID numbers allows for better call management, routing, and customization based on your business needs. It also enables you to establish a local presence in different regions or countries if desired.

Can I add and remove DIDs?


Yes, you can add and remove DIDs based on your needs.

As a user or administrator, you typically have the flexibility to manage your DID numbers. Adding a new DID involves acquiring it from your service provider and configuring it to route calls to the desired destination.

Similarly, when you no longer require a specific DID, you can request its removal or cancellation. The ability to add and remove DID numbers provides businesses with scalability and adaptability in managing their communication infrastructure.

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