A DID allows callers to reach your employee directly without going through an automated attendant, receptionist, or call center. This differs from an internal phone extension, which only works for those calling from within your company’s phone system.
Using DID numbers for key team members boosts connectivity and efficiency as your business grows — whether you’re a small bsuiness building key customer relationships or enterprises strengthening existing relationships or keeping a professional image intact.
In this article, we provide an in-depth look at Direct Inward Dialing, how it works, and its benefits to businesses today.
What Is Direct Inward Dialing?
Direct inward dialing (DID) is a phone system feature that allows external callers to dial directly to an internal extension without having to go through a switchboard or attendant. It assigns each user/extension in an organization a unique external phone number. So external callers can call specific people directly rather than through a receptionist.
To help you use DID, telephone service providers connect a block of telephone numbers to your company’s Private Branch Exchange (PBX) phone system.
Through DID, businesses are able to set up virtual numbers that bypass the main reception lines and go directly to a desk extension or group of extensions. DID can be used with local, premium-rate, or toll-free numbers.
Other common names for DID are direct-dial numbers, direct dial, and direct dial-ins. Essentially, when someone says, “Reach me at my direct number,” this is what they’re referring to.
DID offers businesses convenience, customized call routing, and a more professional image.
What Is a DID Number?
From the perspective of a customer or client, a direct-dial number looks like any standard telephone number. However, DID is a virtual phone number that goes directly to an extension or location in your company. Think of it as a shortcut phone line.
These direct-dial phone numbers point inbound calls to an organization’s phone system. The function of relaying callers to an individual user makes that number “direct.” This dedicated call routing is managed by the VoIP phone system.
Unlike a landline (or POTS line ), these numbers are directly routed through your company’s phone system.
How Does Direct Inward Dialing Work?
Traditionally, DID works in one of two ways: through Public Switched Telephone Network ( PSTN ) lines or Voice over Internet Protocol ( VoIP ) . Let’s start with PSTN.
1. Direct Dialing on PSTN
First, a telephone service provider connects a set of trunk lines to the customer’s hosted PBX . Next, a provider allocates a block of phone numbers and assigns these to the customer as their direct-dial numbers.
When an inbound call reaches one of the direct-dial numbers, it is forwarded to the customer’s PBX via the trunk line. When the call arrives at the PBX, the dialed number and calling party are provided.
Finally, the PBX routes the incoming call directly to one of the business’ phone extensions without the need for an operator or an auto attendant .
Source: Cisco Certified Expert
In older phone systems, direct dial functioned by using analog circuits. This meant that the customer’s equipment had to provide the low-voltage signaling for the phones in the system to work.
The telephone company’s Central Office (CO) would check to determine if the line was operational and disable the circuit if it wasn’t terminating properly.
More recently, traditional phone services offer DID via Primary Rate Interface (PRI) circuits. These require you to have adequate trunk lines leased from the telephone company.
2. Direct Inward Dialing on VoIP
VoIP is the most modern and flexible way to employ virtual direct-dial numbers with the help of SIP trunking . SIP makes the trunk line connections available as needed. These are not physical lines but virtual links across broadband only when you require them.
These virtual links are configured internally, and the numbers are linked to your extensions by a software application. You can do this yourself, or you can have your VoIP provider do it for you.
DID on VoIP is highly scalable. For example, if you decide you’d like to launch a sales campaign next month that requires you to have 20 new trunk lines, you can easily do it yourself.
There’s no need to contact your telephone company, wait for them to allocate a block of numbers, and then send out a technician to physically connect the trunk lines to your business PBX.
3. DIDs for Faxing
The simplest way to use DID as a fax service is to connect your direct-dial line to a fax machine. Sounds simple, right? However, you’d be missing out on the more useful and powerful ways to route fax calls with DID.
A popular practice is to assign a block of direct-dial numbers to a computer that runs a fax server. This allows for multiple fax numbers for your company linked to a particular machine or even multiple devices.
Just like each team member within your company has an email address, you can assign them a fax number. When a fax comes in for a particular individual, it can be routed to the printer in their work area or even their computer and its printer.
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How to Fax Over the Internet (in 5 Easy Steps)
Types of DIDs
The main advantage of DID is it allows direct external access to employees and departments over a single shared telephone line. Companies can allocate numbers based on their communication needs and workflows.
Here are some common types of DID numbers to choose from:
Individual DID numbers: Each employee is assigned their own unique external phone number that routes directly to them. This allows outside callers to reach specific employees without going through a switchboard.
Department DID numbers: A whole department or workgroup shares a single DID number. The number rings a group of phones in that department so calls can be easily handled by multiple people.
Location-based DID numbers: A specific DID number is assigned for each office location or branch of a company. Calls to that number ring phones at only that site.
Toll-free DID numbers: Also known as 800 numbers, these allow external callers to reach employees/departments for free. The 800 number is routed to internal extensions.
Virtual DID numbers: Numbers are not tied to a physical phone line but are hosted virtually. Calls are routed to whatever desk phones, softphones, or mobile phones the company specifies.
Auto attendant DID numbers: Callers hear a menu of dialing options for different people/departments when calling this type of DID number, routing calls without a human operator.
Benefits of Using DID
DID offer plenty benefits compared to traditional phone systems. The ability to dial employees directly is extremely useful for most modern businesses. Here are some notable benefits:
