Do you know any business that doesn't have at least one phone number? Of course not. Having a phone number is an essential part of any business. These ten digit numbers are connected to businesses so that customers can get in touch with the companies that serve them. Along with the development of SIP trunking and VoIP services, DID numbers are becoming increasingly popular, and sooner or later, they are bound to become a "synonym" for telephone numbers.

Although they might be considered as being synonymous, there are quite different from each other. Let's take some timeout to understand what a DID number is and how it is different from traditional phone numbers.


First things first, we need to understand the term "DID number". DID stands for Direct Inward Dialing; it is also known as Direct Dialing Inward (DDI). DID is a service that is offered by telephone companies to provide a set of numbers for calling the company's PBX system. Each employee will have their own personal number without the need for a physical phone line for the connection to the PBX. A single DID number has the ability to route thousands of calls simultaneously to the right extensions. This helps a company manage telephone traffic easily and more efficiently.

DID was designed so a limited number of physical phones lines can be used to call different published phone numbers. A DID can handle every inbound call of a company.


DID numbers work hand in hand with a company's PBX system. Your vendor allocates one or more physical telephone lines, which are called trunk lines, to the customer's PBX, then he provides you with a set of telephone numbers that are in sync with this line. This way, every call will be forwarded to these numbers through the trunk. As soon as the call gets to the PBX system, the dialed destination number will be transmitted for the PBX to route the call to the desired extension.

Let's take a look at an example so you can have a better understanding of what the whole DID number concept entails. Let's assume you have a company with thirty employees and each of them have their own extension. You can rent fifteen trunks from your DID provider and your vendor may allow you to have fifteen ongoing calls. Now, in case all of these lines are busy, your customers will get a busy signal and will be connected as soon as one of the lines is available. The call can also be sent to the voicemail. DID is basically used for fax, voice mail, and live voice transmissions.


Just like the PBX system, DID works quite well for the VoIP system too. And since we are dealing with the VoIP system, there's no need for physical copper lines. PSTN (public switched telephone network) users can reach VoIP users directly since DID numbers are connected with a gateway. The latter connects the PSTN to the VoIP network while routing and translating calls between these two networks for the VoIP user. From the PSTN, calls will be directed to the VoIP user who owns the DID number.


The DID number is a relatively modern technology, thereby having a lot of benefits over the traditional phone number. However, the choice you make solely depends on your business priorities. Listed below are the benefits of the DID number.

1. Flexibility - Establish a local presence in any area with DID. It provides you with the ability to look like part of the local community without having a physical office there. Your customers will call the local number but their calls will be answered from an entirely different place.

2. Cost Cutting - You might have the notion that answering calls from somewhere else is quite possible with traditional phone numbers, what with the call forwarding feature traditional phone numbers are equipped with. And the thing is, you are right. However, when it comes to your budget, that isn't the best solution. When you make use of DID with VoIP, long distance nationwide calls won't be charged. Your DID is a virtual system; it isn't connected to any physical equipment.

3. Reduced Labor Cost - DID reduces your expenses on your employees. Since DID is assigned to each of your employees, the callers will get to their desired destination by dialing the extension number, thereby minimizing the need for a receptionist or an operator. 

4. Increased Efficiency - By assigning DID numbers to each of your employees, your customers or callers will be able to get to them easily and quickly. This will, in turn, minimize hold times and efficiently manage call traffic.

5. Positive Customer Experience - Your customers will feel more cared for as they will be connected directly to the appropriate personnel. This will enhance your customer's personal experience, thereby guaranteeing positive feedback.

Now, you are well equipped with the right knowledge to help you understand and decide on which number is best for your company. You now know all the advantages of DID and how it will benefit your business. It's now left to you to make the final decision. If your call volume is low and you are satisfied with having a few lines, then you can keep your traditional phone number. However, you need to know that even small businesses are taking advantage of DID numbers. Your business might need the flexibility offered by DID so it can thrive even more. Be open, let your business keep up with technology and prosper with it. 

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