Connect a Yeastar P-Series PBX to a NumberGroup SIP trunk

This is the working setup for adding a NumberGroup SIP trunk to a Yeastar P-Series PBX (P550, P560, P570 — appliance or cloud edition). Yeastar ships certified templates for some carriers; there isn't one for NumberGroup specifically, so we use the General template with a Register Trunk — the right choice because NumberGroup authenticates your PBX with a username and password. Takes about five minutes once your trunk credentials are open.

When you ask us to set up the trunk, request Send Numbers As set to "International (+xx)" — that presents inbound DDIs in E.164 (+44…), which is the cleanest format for the P-Series to match against your inbound routes.

Step 1: add the trunk

Log in to the P-Series web portal and go to Extension and Trunk → Trunk, then click Add.

• Name: NumberGroup (or anything memorable)
• Trunk Status: Enabled
• Select ITSP Template: General

Step 2: detailed configuration

In the detailed configuration section, choose the trunk type and enter your NumberGroup values:

• Trunk Type: Register Trunk
• Transport: UDP
• Hostname/IP: sip.numbergroup.com
• Port: 5060
• Domain: sip.numbergroup.com
• Username: T-AAAAAA-NNN from the email we send you (e.g. T-102377-001)
• Password: your trunk password from the email we send you
• Authentication Name: T-AAAAAA-NNN — the same value as the Username

Why Username and Authentication Name match: Yeastar's own guide notes the Authentication Name is "in most cases, the same as the username" — and on a NumberGroup trunk it always is. Both take your T-AAAAAA-NNN. Leave Enable Outbound Proxy off.

Step 3: add your DDIs

Click the DIDs/DDIs tab → Add to tell the PBX which numbers it owns:

• For one number — Create Method Single DID, then enter it in the DID/DDI field
• For a block — Create Method DID Range, then enter the start and end numbers in DID Range
• DID/DDI Name (optional) helps you distinguish inbound calls
• Click Confirm

Then click Save and Apply on the trunk.

Step 4: inbound and outbound routes

A trunk on its own doesn't route calls — point it at your extensions:

• Inbound: assign this trunk to one or more Inbound Routes so calls to your DDIs ring the right extension, ring group or IVR.
• Outbound: assign the trunk to an Outbound Route so your extensions dial out through NumberGroup. Set the route's caller ID to one of your NumberGroup DDIs (an invalid CLI is the usual cause of an outbound 403).

The exact route screens are in Yeastar's own admin guide, linked at the foot of this page — we keep the click-path with them so it stays current with your firmware.

Step 5: verify registration

• Back on Extension and Trunk → Trunk, the trunk shows the OK status icon once it has registered successfully
• We can confirm the trunk has registered our side — ring us or check your email for the "trunk live" confirmation
• Place a test call out, and ring one of your DDIs from a mobile to test inbound

When it doesn't work

Trunk never shows the OK icon

• Wrong Username, Authentication Name or Password — check them against the email we sent when we set up the trunk (a stray trailing space in the password is a common culprit)
• Hostname/IP and Domain must both be sip.numbergroup.com exactly
• Transport must be UDP on port 5060

Outbound fails with 403

The caller ID your Outbound Route presents isn't one of your NumberGroup DDIs. Set it to a valid DDI you own.

One-way or no audio

• Disable SIP ALG on your router — it rewrites SIP and breaks the media path
• Confirm the P-Series' NAT settings reflect your real public IP if the PBX is behind NAT

Set the fraud caps before going live

Ask us to set the trunk's Fraud Detection Simultaneous Calls and a Daily Spend ceiling a little above your real peak. If a compromised extension tries to dial through out of hours, the trunk auto-disables before the bill runs up. See our UK telecom fraud guide.

Source: the device navigation in this guide follows Yeastar — Create a SIP Register Trunk (P-Series Administrator Guide). We keep the click-path with the manufacturer so it stays current — the NumberGroup trunk values above are the part specific to your account.