Trunks
Creating a SIP Register Trunk on Yeastar P-Series Cloud Edition
SIP trunk
register trunk
VoIP provider
PSTN
Introduction
A SIP trunk connects your PBX to a VoIP carrier, enabling inbound and outbound calls to real phone numbers. The most common type is a Register Trunk, where the PBX registers to the carrier's SIP server (similar to how a phone registers to the PBX). X2Comms can supply SIP trunks alongside your Cloud Edition service.
What you need from your VoIP carrier
- SIP server hostname or IP (e.g.
sip.carrier.co.uk) - SIP port (usually
5060) - Username and password
- Your inbound phone number(s) / DDI(s)
Menu path
Extension and Trunk > Trunk, click Add.
Step-by-Step Guide
Step 1 — Basic section
| Field | What to enter |
|---|---|
| Name | Descriptive name, e.g. X2Comms SIP |
| Trunk Status | Enabled |
| Select ITSP Template | Choose your carrier from the list, or select General if not listed |
Step 2 — Detailed configuration section
Change Trunk Type to Register Trunk, then fill in:
| Field | What to enter |
|---|---|
| Transport | UDP (most carriers) — use TCP or TLS only if your carrier specifies |
| Hostname/IP | Your carrier's SIP server (e.g. sip.carrier.co.uk) |
| Port | 5060 (default) |
| Domain | Usually the same as Hostname/IP; enter the domain if your carrier specifies a different one |
| Username | Your SIP account username |
| Password | Your SIP account password |
| Authentication Name | Usually the same as Username |
Step 3 — DIDs/DDIs tab
Add your inbound phone number(s) here so the PBX knows which calls belong to this trunk:
- Click the DIDs tab.
- Click Add.
- Enter your DDI number (e.g.
01234567890) in the DID/DDI field. - Add additional DDIs if you have multiple numbers.
- Click OK.
Step 4 — Save
Click Save and Apply.
Step 5 — Verify registration
Go back to Extension and Trunk > Trunk. Within 30–60 seconds the trunk status should change to Registered (green).
Tips
- Trunk not registering? Check the username, password, and hostname are exact — copy-paste from your carrier's welcome email rather than typing.
- Firewall issues? Cloud Edition handles NAT automatically, but confirm your carrier's SIP server is not blocking traffic from the PBX's IP range.
- One-way audio on calls? This is usually a codec mismatch. Go to the trunk's Codec tab and ensure G.711 a-law (alaw) is listed first for UK carriers.
- Caller ID on outbound calls — set the Outbound Caller ID on the trunk or per-extension under Extension > Outbound Caller ID (DOD).
Summary
The SIP trunk is registered and ready. Now create inbound and outbound routes to start routing calls through it.