What Is an Extension
An extension is a short internal number — typically 3 or 4 digits — that identifies a specific phone or user within your DVGVoIP system. Extensions are used for calls that stay within your organization. If your colleague is on extension 102 and you are on extension 101, you can call them by simply dialing 102 from your phone or web client.
Extensions exist only within your phone system. Someone calling from outside your business cannot dial your extension directly — they need to reach you through a phone number that connects to the public telephone network first.
In 3CX, each extension corresponds to a user account. That account controls your voicemail, call forwarding rules, status, chat identity, and login credentials for the web client and mobile app.
What Is a DID (Direct Inward Dial) Number
A DID, or Direct Inward Dial number, is a real telephone number that people outside your organization can call. When someone dials your DID, the call arrives at your phone system and is routed to the correct extension or group of extensions based on rules DVGVoIP has configured for you.
DID numbers are assigned by DVGVoIP through our carrier connections. They look like any normal phone number — for example, a local Thunder Bay number with an 807 area code. You can have one DID shared across all staff, individual DIDs for each employee, or a combination of both.
Example: Your business main number (e.g., 807-555-0100) is a DID that rings your main receptionist extension or auto-attendant. A sales rep might also have a personal DID (e.g., 807-555-0105) that rings directly to their extension, bypassing the main menu.
How Outside Calls Reach Your Extension
When someone calls your business number, the call travels through the public telephone network and arrives at your 3CX system. From there, 3CX uses its inbound routing rules to decide where to send it. There are several common routing patterns:
| Routing Type | How It Works |
|---|---|
| Auto-Attendant (IVR) | Caller hears a greeting and presses a number to reach a department or person. Common for businesses with multiple departments. |
| Ring Group | The call rings multiple extensions simultaneously. The first person to answer takes the call. |
| Direct to Extension | The DID is mapped directly to one extension. Useful for personal direct lines. |
| Queue | Callers wait in a queue and are connected to the next available agent. Common for support or sales teams. |
DVGVoIP configures your inbound routing during setup. If you need to change how calls are handled — for example, adding an after-hours message or changing which extensions ring — contact us and we can update your routing rules.
Shared Lines vs. Direct Lines
A shared line means that multiple people answer calls that come in on the same number. A common example is a main business number that rings all staff or a reception desk. Anyone who picks up handles the call.
A direct line (also called a personal DID) is a number assigned specifically to one person. Callers who know the direct number can reach that person without going through a menu or receptionist. Direct lines are common for managers, sales staff, or anyone who receives a high volume of individual calls.
In 3CX, both arrangements are managed through ring groups and inbound routing rules. You can have both types active on the same system — for example, a shared main number plus direct lines for specific staff members.
Finding Your Extension Number
Your extension number is shown in several places within the 3CX web client:
- Log into the 3CX web client at your system's web client URL.
- Click on your name or avatar in the top left corner of the sidebar to open your profile.
- Your extension number is displayed prominently in the profile panel, along with your name and email address.
- You can also see your extension number in the Contacts section — search for your own name and your extension will appear in the results.
Your extension number was also included in your original welcome email from DVGVoIP. If you need to find out your DID number (your outside-facing direct number), this is also in the welcome email, or you can contact DVGVoIP support and we can confirm it for you.
Dialing External Numbers
When making outbound calls to numbers outside your organization, the dialing format depends on how your system is configured by DVGVoIP. There are two common setups:
| Config | How to Dial a Local Number | How to Dial Long Distance |
|---|---|---|
| 10-digit dialing (most common) | Dial the full 10-digit number including area code (e.g., 8075550100) | Dial the full 10-digit number — no prefix needed |
| 9 + number (legacy config) | Dial 9 then the 7-digit number (e.g., 9 5550100) | Dial 9 1 then the 10-digit number |
DVGVoIP configures most new systems with 10-digit dialing, which is simpler and consistent with how most people already dial on mobile phones. If you are unsure which format your system uses, try dialing a local number without a prefix first. If the call does not connect, try adding 9 as a prefix.
Note: When calling other extensions within your system, never add area codes or prefixes — just dial the 3 or 4 digit extension number directly.
Need Help?
Open a support ticket by emailing support@dvgvoip.com before calling — this helps us resolve your issue faster. Or call (807) 700-7111.