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Connect Your Own Number

Use a phone number you already own at another provider with your voice agent. The number stays with that provider. You only change where it sends calls, so nothing is purchased or ported and there is no monthly charge.

If you don't have a number yet, buying one is easier. See Voice Agents.

This guide covers:

  1. Which option to use
  2. Option A: Carrier or SIP trunk
  3. Option B: Phone system
  4. Provider setup
  5. Managing a connected number
  6. Troubleshooting
  7. Frequently Asked Questions

Which option to use​

Calls are handed over using SIP. How you connect depends on where your number is today:

Your number is withUse
A carrier or SIP trunk provider (Twilio, Telnyx, Vonage, Bandwidth, SignalWire)Option A — we give you a SIP address and credentials and you point the number at it.
A phone system (RingCentral, Zoom Phone, 3CX, Dialpad, FreePBX, Asterisk)Option B — you add a SIP device for the agent and we sign in to it as an extension.
A traditional landline or mobile carrier with no SIP settingsNot connectable. Buy a number on the platform and turn on call forwarding to it at your carrier.

If you can't find any SIP, trunk or extension settings at your provider, the last row applies.

Option A: Carrier or SIP trunk​

  1. Open your voice agent and click the phone icon in the message box. In the Phone Numbers panel, click Connect an existing number. If the agent already has numbers attached, open the Connect your number tab instead.
Phone Numbers panel offering Buy a new number or Connect an existing number
  1. Pick the country, enter the number and choose It's with my carrier or SIP trunk. Leave authentication on Username & password (recommended) and click Connect number.
Connect your number tab with the carrier or SIP trunk option selected
  1. Copy the details from the SIP connection details dialog:
FieldValue
SIP hostsip.abacus.ai
SIP username / SIP passwordGenerated for this number
Route your number toThe full address, for example sip:+14155550123@sip.abacus.ai
SIP connection details dialog

You can open this dialog again later from the key icon on the number's row.

  1. In your provider's dashboard, open the number's voice or routing settings and set the destination to the Route your number to address. If the provider asks for the host and the number separately, use the SIP host. Enter the SIP username and password where it asks for SIP credentials and save. See Provider setup for Twilio and Telnyx.

  2. Call the number from your mobile. The agent should answer within a couple of rings.

Fixed IP addresses​

Some trunks, including Twilio Elastic SIP Trunking, don't send credentials. They identify themselves by source IP instead. If your provider's documentation says so, choose Fixed IP addresses in step 2 and add the provider's signalling IPs or ranges under Allowed source IPs (up to 20 entries). Then point the trunk at sip-trunk.abacus.ai, port 5080. Calls from any other address are rejected.

Option B: Phone system​

  1. In your phone system's admin console, add a new SIP device (also called a generic SIP phone or extension) and assign your number to it. Note the SIP host (also called registrar, SIP server or domain), username (auth ID) and password it gives you.
tip

Create a dedicated device for the agent. If you reuse someone's extension login, the agent may answer calls meant for their phone.

  1. In the Connect your number tab, enter the number and choose It's on my phone system. Paste the Provider SIP host, Extension username and Extension password. Open Advanced options only if your phone system needs TCP or TLS instead of UDP, or a non-standard port. Add the port to the host, like sip.example.com:5096. Click Connect number.
Connect your number tab with the phone system option selected
  1. Within about a minute the number's row reads Registered to your provider. Call the number to test.

The password is stored encrypted and can't be viewed again after saving. You can change the host, username, password or transport later without disconnecting.

Provider setup​

These are the providers we have tested end to end. Others work the same way as long as they can route a number to a SIP address (Option A) or issue SIP device credentials (Option B).

Twilio​

Elastic SIP Trunk (recommended, no code). Twilio doesn't send credentials on trunk calls, so use Fixed IP addresses.

  1. In Abacus.AI, connect the number with Fixed IP addresses and add every signalling IP Twilio publishes for your edge location.
  2. In the Twilio Console, open Elastic SIP Trunking → Trunks and pick or create a trunk.
  3. Under Origination, add the SIP URI sip:sip-trunk.abacus.ai:5080. Twilio fills in the dialled number itself.
  4. Under Numbers, associate your number with the trunk. This doesn't release it from your account.

TwiML (number stays on Programmable Voice). Connect the number with Username & password. Then in Phone Numbers → Manage → Active numbers, open the number and set A call comes in to a TwiML Bin or your own webhook that returns:

<Response>
  <Dial>
    <Sip username="YOUR_SIP_USERNAME" password="YOUR_SIP_PASSWORD">sip:+14155550123@sip.abacus.ai</Sip>
  </Dial>
</Response>

Replace the placeholders and the number with the values from SIP connection details. If calls fail, check Monitor → Logs → Calls in the Console. It shows why Twilio couldn't reach the SIP address.

Telnyx​

Telnyx sends calls to us (FQDN connection).

  1. In the Telnyx portal, create a SIP connection of type FQDN with destination sip-trunk.abacus.ai, port 5080, and number format +E.164.
  2. Assign your number to the connection.
  3. In Abacus.AI, connect the number with Fixed IP addresses and add Telnyx's signalling IPs for your region.

We sign in to Telnyx (Credentials connection).

  1. Create a SIP connection of type Credentials and assign your number to it.
  2. In Abacus.AI, choose It's on my phone system, with sip.telnyx.com as the host and that connection's username and password.

Managing a connected number​

Connected numbers show a Your number badge and read Connected over SIP or Registered to your provider. Transcripts and the Call activity tab work the same as for rented numbers. There is no outbound test call button for connected numbers, because test calls go out over our own carrier. Call the number from any phone instead.

Attached numbers list showing a connected number with the Your number badge
  • SIP credentials (Option A): click the key icon on the number's row to view them again or Rotate password. The old password stops working immediately, so update your provider right after. The same dialog has Use IP allowlist if you need to switch to fixed IPs.
  • Source IPs: click the shield icon on the row. Saving replaces the whole list.
  • Disconnect: click the trash icon on the row and confirm. The number stays with your provider. Change its routing there too, or callers will hear a failure.

Troubleshooting​

Calls don't reach the agent​

Check that the number matches digit for digit, including the country code, and that the destination at your provider is exactly the address shown. For Option B, wait a full minute and confirm the number is assigned to the device you created.

Callers hear a busy tone or "the call cannot be completed"​

Your provider is being rejected. Usually the username or password at the provider is wrong (rotate and re-enter it), the call is coming from an IP that isn't on your allowlist, or your organization is out of credits.

The agent answers but there is no audio, or audio in one direction​

A firewall is blocking the audio stream. Ask your network admin to allow SIP and RTP traffic.

"Your organization has reached its daily limit of connected numbers"​

You can connect up to 10 numbers per day. Try again tomorrow, or contact support if you need more.

Frequently Asked Questions​

Does a connected number cost anything?​

There is no monthly charge. Calls are billed per minute the same as calls to a rented number. Your provider may charge you separately for carrying the call to us.

Which countries are supported?​

Any country where your provider can route the number to a SIP address or let us sign in as an extension. Some carriers and some countries don't allow routing to an external SIP endpoint, so check with your provider first.

Do you port or take over my number?​

No. It stays in your provider's account and you can change the routing back at any time.

Can I connect one number to two agents?​

No, a number connects to one agent at a time. An agent can have up to 10 numbers, connected and rented combined. Contact support if you need more.

Can the agent transfer calls, or make outbound calls from a connected number?​

Call transfer works on connected numbers. Outbound calls, test calls and PIN access are only available on rented numbers today.

What if I disconnect the number by mistake?​

Connect it again. You will get new SIP credentials (Option A) or re-enter your phone system's login (Option B), and will need to update your provider with the new details.

Still Need Help?​

If you're still stuck, contact support — we're here for you.