GuidesCalls
Bring your own carrier
Connect the phone line you already pay for, a SIP trunk or your own phone system, and use its numbers in Crulon for calls.
If you already have numbers with a carrier, or run your own phone system, you can connect it to Crulon and use those numbers for calls: in Call Flows, with your team, with the AI agent and as caller ID. Crulon calls this a carrier.
- Plan
- Scale
- Where
- Settings > Carriers
- Who can do it
- Workspace Admins and Managers, to start
- You need
- Your carrier’s SIP connection details, and access to its portal or your phone system’s settings
It’s also how workspaces in Australia and New Zealand get numbers, since Crulon doesn’t sell numbers there.
How it connects
A carrier connects in two directions, and each side needs something from the other.
Incoming calls
Your carrierCrulonsip:+14155550100@acme.sip.crulon.ai:5061;transport=tls
Outgoing calls
CrulonYour carriersip.mycarrier.com, from Crulon’s published addresses
- Incoming: your carrier sends each number’s calls to an address Crulon gives you, one per number. Crulon checks the call really came from your carrier, by a password or by the addresses your carrier calls from.
- Outgoing: Crulon sends calls to your carrier’s address. Your carrier checks they really came from Crulon, by a username and password it gave you or by Crulon’s addresses.
Connect a carrier
Create the carrier
Open Settings > Carriers and select New carrier. Under Your carrier:
| Field | What to enter |
|---|---|
| Name | Anything that labels it for your team, such as “Main carrier” |
| Carrier address | Where Crulon sends your outgoing calls, such as sip.mycarrier.com. Your carrier gives you this |
| Transport | TLS if your carrier supports it, otherwise UDP. TCP isn’t supported |
| Port | Your carrier’s port. On TLS, Crulon always uses 5061 |
| Encrypt media (SRTP) | Turned on for you with TLS. Your carrier must support it |
| Receive calls, Place calls | Which directions this carrier is for. Both are on to start |
Under Incoming calls, choose how Crulon checks a call came from your carrier:
- By password (recommended): Crulon makes a username and password for you to enter at your carrier.
- By source address: list the addresses your carrier calls from, one per line. Use it only if your carrier can’t send a password. Carriers change these, so check them if incoming calls stop.
Under Outgoing calls, choose how your carrier checks a call came from Crulon:
- By a username & password my carrier gave me: enter them.
- By our source address: nothing to enter; you allow Crulon’s addresses at your carrier.
Then set:
- Calling zone: which destinations this carrier treats as domestic. It’s about the carrier, not your workspace: a US business can use an Australian carrier.
- International calling: on to start. When on, calls outside the zone go to your carrier as international calls.
- Channel limit: how many calls your carrier allows at once, 10 to start. Crulon never places more outgoing calls than this.
Read the emergency calling notice, tick the box, and select Create carrier.
Set up incoming calls at your carrier
On the carrier’s page, follow Set up incoming calls at your carrier. This is the one step Crulon can’t do for you.
- Point each number at the address Crulon shows for it. If your carrier asks for the parts separately, the page lists the domain, the user (the number itself) and the port.
- If you chose By password, select Generate a password, then enter the username and password in your carrier’s settings. The password is shown once.
The page has hints for where to find these settings at some popular carriers.
Let Crulon through at your carrier
If the carrier places calls, follow Let Crulon through at your carrier. Hosted carriers usually accept Crulon’s calls already. A phone system you run yourself, such as FreePBX, 3CX or Asterisk, usually needs its firewall to allow SIP and RTP (UDP) from the addresses Crulon lists. Until then, outgoing calls time out with no answer.
Attach a number
Select Attach a number, or open Settings > Phone numbers, select Add a new number and choose Bring your own carrier (BYOC). Pick the carrier, enter the number in full international format, such as +14155550100, and give it a label. Add each number the same way.
Test
Select Test connection. It checks the carrier is set up correctly, and the status shows Ready once it can carry calls. It doesn’t place a call, so then call one of the numbers from another phone, and make a call out. Only a real call proves it works end to end.
Warning
Your carrier must send incoming calls with the number in full international format, starting with +. If it sends fewer digits, Crulon can’t match the number, and the call fails without showing up in Crulon.
What numbers you bring can do
- Calls only. They can’t send or receive texts.
- Everything else a number does in Crulon: Call Flows, Default ring, members and caller ID, for your team, desk phones and the AI agent.
- Outgoing calls go through the carrier that owns the caller ID number. There’s no fallback: if that carrier can’t place a call, the call is refused rather than sent another way.
- Moving a number to another carrier: select Move on it. It keeps working until the move is done.
- Removing a number stops it reaching Crulon. Your carrier still holds it, and you can add it back. A number can’t be removed while a Call Flow is on it: take it off the flow first.
Emergency calls
Emergency calls on a number you bring depend on your carrier:
- Crulon passes the number dialled straight to your carrier, and doesn’t know whether it connects.
- Crulon can’t register an emergency address for a number it doesn’t provide. Register it with your carrier.
- Your carrier bills these calls and decides where they go.
Only a person can dial emergency services, from the browser or a desk phone. AI agents and campaigns can’t.
Calling rules
- High-risk protection is on to start and blocks premium-rate ranges. You can turn it off for a carrier; Crulon records who did it and when, and any charges are on your carrier bill.
- International calling follows the carrier’s setting and calling zone. Turn it off to keep a carrier to its zone.
- Channel limit applies to every outgoing call on the carrier: your team’s, the AI agent’s, campaigns’ and transfers. When it’s full, new outgoing calls are refused until one ends.
Transfers
Transfers to outside numbers on your own carrier ask your carrier to move the call. If your carrier refuses, a teammate stays connected to the caller and sees The carrier refused that transfer. Ask your carrier to allow call transfers (SIP REFER) on the trunk.
Health and problems
The carrier page shows its status, its health from recent calls, when it was last checked and the last error. Crulon doesn’t send alerts when a carrier has problems, so check the page if calls stop.
- If your carrier rejects Crulon’s username or password on an outgoing call, outgoing calls on that carrier stop until you fix it. Select Update carrier username & password, or Test connection once your carrier is fixed.
- Last incoming call: never means no call has reached Crulon on this carrier yet.
Billing
Crulon doesn’t charge for calls on your own carrier: your carrier bills you for them. AI minutes still count when the AI agent is on a call. Numbers you bring aren’t charged, but they count toward the numbers your seats include, so a number you buy from Crulon afterwards may be an additional number.
If your workspace moves off Scale, calls on your carriers stop and nothing is deleted. They work again if you return.
Change or remove a carrier
- Edit settings changes the connection details, calling zone, international calling and channel limit.
- Update carrier username & password replaces the details your carrier gave you.
- Generate a new password replaces the password your carrier uses to reach Crulon. The old one stops working at once.
- Delete carrier removes it for good. Move or remove its numbers first.
If something goes wrong
Check each number points at its own address from the carrier page, including the port, and that your carrier sends the number with a leading +. If you verify by password, check the username and password at your carrier, or generate a new one. If you verify by source address, check your carrier hasn’t changed its addresses.
Your carrier or phone system isn’t letting Crulon through. Allow SIP and RTP (UDP) from the addresses on the carrier page.
Choose a Calling zone under Edit settings. Incoming calls still work.
The number dialled is outside the carrier’s calling zone. Turn International calling on for the carrier, or add the right zone.
Every channel is in use. Wait for a call to end, or raise the Channel limit if your carrier allows more.
Move or remove its numbers before you delete it.
Make sure your carrier offers the standard G.711 codecs (PCMU or PCMA), and that RTP over UDP is allowed from Crulon’s addresses.
Last updated 18 Oct 2026