What is a DID, and how do you give each employee a direct number?

Definition and origin

DID stands for Direct Inward Dialing. In the old world, an organization's PBX had several lines from the phone company, and all of them came in to the secretary. To reach a particular employee, you had to ask to be transferred. DID solved this: the phone company assigned the organization a range of numbers, and passed the PBX, along with each call, the number that was dialed. The PBX knew how to send each number to the matching extension.

In Europe it is sometimes called DDI — Direct Dial-In. It's the same idea under a different name.

In a cloud PBX the idea is even simpler. Every number the organization holds is a separate "door," and you can decide where it leads: to an extension, a group, a queue, a voicemail box or an IVR menu. A direct number is a door that leads to one person.

What has also changed in the cloud is flexibility: with an old PBX, adding direct numbers sometimes required requesting a new range from the phone company and configuring it in the equipment at the office. Today you add a number, set where it leads, and that's it.

How it works

1. A customer dials the treasurer's direct number.
2. The public network passes the call to the PBX's provider.
3. The PBX receives the call together with the number that was dialed.
4. Based on the number, it knows the call is meant for extension 210 — and rings there, with no menu.
5. If the treasurer doesn't answer, the call continues to the destination you set: voicemail, a colleague, or the front office.

From the customer's point of view, they dialed a completely ordinary number. From the organization's point of view, there's no need for a separate line for the treasurer — just an additional number routed to his extension.

The important part in step 3 is that the PBX knows which number was dialed, and not only who called. Without this information, all calls would look the same to it, and it would send all of them to the same place.

Direct number vs. extension number

The two terms are often confused, but they are different:

You can also combine them: a main number with a menu that says "If you know the extension number, dial it now." This is an alternative way to reach a person directly, without an additional number for each one. See IVR menu.

In practice, many organizations use both ways together: direct numbers for those who receive many calls from outside, and dialing an extension from the menu for everyone else. This way you don't need a number for every employee, and yet everyone is reachable.

Who It's For

• People who talk a lot with regular customers — a bookkeeper, a registration coordinator, a fundraiser. The customer wants to reach them, not a menu.
• Departments — a direct number for accounting, a direct number for registration. The number leads to a group of extensions or to a queue, and not to one person.
• Branches — a local number for each branch, leading to that branch's extensions.
• A line for a specific service — a number for fax, for a gemach, for a phone-in class.
• Management — a number that regular customers don't know, for partners and suppliers only.

Not every employee needs a direct number. A small organization usually gets by with a main number and a menu. A direct number is justified when there are customers who really call a particular person regularly.

A useful rule of thumb: if the secretary transfers more than a few calls a day to the same person, and always from the same customers — he probably needs a direct number.

The number the customer sees

A direct number works in both directions. Incoming — it leads to the extension. Outgoing — you can set it so that when the extension calls out, the customer sees the direct number and not the main one. See Caller ID.

This is a decision worth making consciously:

• Showing the direct number — the customer will call back the employee directly. Convenient for regular customers, but if the employee is on vacation, the call needs to know where to go next.
• Showing the main number — the customer will call back the front office or the menu. Less personal, but there is always someone to answer.

Many organizations choose by role: sales and collections staff show a direct number, and everyone else shows the main one.

And what about an internal call? When an employee calls another employee on the same PBX, what usually appears is the extension number or the name, and not the direct number. The direct number is used for the outside world.

What happens when there's no answer

The danger with a direct number is a call that rings at an empty extension. So for every direct number you need to set what happens when the person doesn't answer:

• After a few rings — to a personal voicemail box, with a greeting in his own voice.
• Or — to a colleague or the front office.
• Outside working hours — a message with the hours of operation.
• On vacation — a temporary forward to a substitute.

And what about an employee who leaves? His direct number shouldn't just disappear. You route it to his replacement, or to the front office, so that longtime customers who call him still reach someone.

Tip: a personal greeting in the voicemail box of a direct number — "You've reached Rivka in accounting" — reassures the caller that they reached the right place, even when no one answers.

Smart numbering: last digits matching the extension

When you get a range of consecutive numbers, you can build consistent numbering: the last four or three digits of the direct number are the same as the extension number. For example, extension 210 — a direct number ending in 210.

The advantage: anyone who knows the extension knows the direct number, and vice versa. A new employee doesn't need a list, and a customer who remembers "extension 210" can dial directly.

The disadvantage: it's not always possible to get a consecutive range, especially when porting existing numbers. In that case, a clear table is better than "almost consistent" numbering that confuses. See Extension numbering plan.

A direct number for an employee who isn't in the office

In a cloud PBX, a direct number isn't tied to a desk. The extension it leads to can be:

• A desk phone at the office.
• A softphone on a computer at home or on a mobile phone.
• A SIM extension on a mobile phone, including a kosher phone.
• Several devices together, ringing at the same time.

This way, a fundraiser who is on the road most of the day can receive calls to his direct number anywhere, and make calls showing the same number — without giving customers his private cell phone.

And when he returns to the office, the same number also rings on his desk phone. The number stays fixed; only the device that answers changes depending on where he is.

Common mistakes

• A direct number with no destination for no answer — the call rings until the caller gives up.
• A direct number that doesn't appear anywhere — the employee got a number, but it isn't in the signature, on the card, or on the website. No one uses it.
• Calling out with a number that isn't routed — the extension shows a certain number, but incoming calls to it aren't set up. The customer who calls back gets stuck.
• Forgetting the number of an employee who left — it keeps ringing at an extension where no one is.
• Too many numbers — dozens of direct numbers and no one remembers who holds them. It's worth keeping an up-to-date table.

Most of these mistakes can be prevented by one simple test after every change: a call from a cell phone to the direct number, once when it's answered and once when it isn't, and checking that it arrives exactly where you planned.

An example from the field

At the nonprofit "One Heart for the Community" (a made-up name), all phone donations came to the main number, and from there were transferred manually to the donations coordinator. During the holiday season the secretary transferred dozens of calls a day, and donors waited.

The nonprofit added a direct number for the coordinator, and printed it on the thank-you letters and on the receipts. Regular donors started dialing directly. When the coordinator isn't available, the call goes to a small queue of two volunteers. The secretary went back to her own work, and the main number stayed for everything else.

And at the end of the season, the call history showed how many donors called the coordinator directly — information that helped plan the next season.

Direct numbers and tracking

A direct number also provides information. When each department or each campaign has its own number, the call history shows exactly how many calls reached each one:

• How many calls reached the registration line in the first week of registration.
• How many donors called the number printed on the thank-you letter.
• How many calls to the collections direct number went unanswered, and at what hours.
• Which branch receives more calls, and when.

This way a direct number is not only a convenience for the customer, but also a measurement tool. Instead of guessing which advertising worked, you can see.

Before adding direct numbers: planning questions

1. Which people do customers really call directly, and which only through the front office?
2. Will the number lead to a person, a group or a queue?
3. What will happen when there's no answer, and outside working hours?
4. Which number will be shown to the customer on outgoing calls?
5. Where will the number be published — signature, card, website, letters?
6. Who is responsible for updating it when an employee changes roles or leaves?

Six clear answers in advance prevent most of the mistakes we described above.