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

This is the working setup for adding a NumberGroup SIP trunk to a Yeastar S-Series PBX (S20, S50, S100, S300). NumberGroup isn't one of Yeastar's pre-loaded provider templates, so we use the General country 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 S-Series to match against your inbound routes.

Step 1: add the trunk

Log in to the S-Series web portal and go to Settings → PBX → Trunks, then click Add.

• Name: NumberGroup (or anything memorable)
• Select Country: General
• Trunk Type: Register Trunk

Step 2: enter the trunk details

Fill in the trunk information with your NumberGroup values:

• Transport: UDP
• Hostname/IP: sip.numbergroup.com
• 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
• From User: T-AAAAAA-NNN — also the same as the Username

Why Username, Authentication Name and From User all match: on a NumberGroup trunk all three take the same value — your T-AAAAAA-NNN. That's the single most common thing people get wrong on the S-Series, because the form lets you set them independently.

Step 3: add your DDIs

On the S-Series, DID numbers live under the trunk's Advanced tab (the S-Series only needs these set if your DID number differs from the trunk authentication name — which it does with NumberGroup):

• Open the trunk's Advanced tab
• Enter your number in the DID Numbers field
• Tick DNIS Name and give it a label if you want the called number identified on the ringing phone
• Click + to add further DDIs, then Save and Apply

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

• Go to PBX Monitor — 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 in PBX Monitor

• Wrong Username, Authentication Name, From User 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 S-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 VoIP Register Trunk (S-Series Document Center). We keep the click-path with the manufacturer so it stays current — the NumberGroup trunk values above are the part specific to your account.