Connect an Htek desk phone to a NumberGroup SIP trunk
Map your NumberGroup SIP trunk credentials onto an Htek UC-series IP phone — where the server lives on the Profile page and the credentials on the Account page. Field-by-field mapping table plus Htek's own guide.
This registers an Htek UC-series IP desk phone directly to a NumberGroup SIP trunk — no PBX in between. Htek splits the config across two pages, and that's the one thing worth getting right: the server lives on the Profile page, the credentials live on the Account page, and you bind the Account to the Profile.
When you ask us to set the trunk up, request Send Numbers As set to "United Kingdom" so Caller ID arrives in the familiar 01214001262 format.
The credentials and settings your device needs to register against the NumberGroup SIP trunk are:
- Domain / registrar:
sip.numbergroup.com - Authorisation ID (also called SIP username): looks like
T-AAAAAA-NNNe.g.T-102377-001 - Password: a random string we generate per trunk
- User-Agent Type: we set this our side to match your device (e.g. 3CX Phonesystem, DDI in R-URI (Asterisk), RFC3261 Standard Trunk) so DDIs present in the format your equipment expects
- Send Numbers As: also set our side — pick the format that works best for your platform:
- International (+xx) — true E.164 (
+441214001262) for 3CX, Cisco, Yealink and most modern PBXs - International (xx) — bare digits (
441214001262) for Asterisk / FreeSWITCH dialplan regex - United Kingdom — UK format (
01214001262) for direct-register desk phones / softphones where humans read the Caller ID
- International (+xx) — true E.164 (
- Allowed IPs (optional): for an extra security layer we can lock the trunk to only register from your office IPs — tell us which when you ask
Once you have the credentials, the rest of this guide walks through the device-side config. If you'd rather skip the config altogether, ask us — we'll do it for you on most common PBXs and phones.
Field mapping
Htek owns the click-path and keeps it current — the table below maps each NumberGroup value to its exact field, and crucially which of the two pages it sits on.
Browse to the phone's IP from a computer on the same LAN. The settings are split across two pages: Profile → Basic (the server and transport) and Account → Basic(set Account Active = Yes, select the Profile, then enter the credentials). You must bind the Account to the Profile or it won't register.
Full navigation is in the manufacturer's own guide: Htek phones wiki (htekdesk.atlassian.net) — find your model. We keep the click-path with them so it stays current — the table below is the part that's specific to your NumberGroup trunk.
| NumberGroup value | Htek UC-series field |
|---|---|
| sip.numbergroup.com | Primary SIP Server (Profile → Basic) |
| UDP | SIP Transport (Profile → Basic) |
| T-AAAAAA-NNN | SIP User ID (Account → Basic) |
| T-AAAAAA-NNN | Authenticate ID (Account → Basic) |
| your trunk password | Authenticate Password (Account → Basic) |
| RFC2833 | DTMF (Profile → Advanced) |
| PCMU, PCMA, G722, G729 | codec list (Profile → Codec) |
Split-field note: Htek separates SIP User ID from Authenticate ID. On a NumberGroup trunk both take the same value — your T-AAAAAA-NNN.
Verify
- The line shows registered on the phone's screen / Account status within a few seconds
- We can confirm the trunk has registered our side — ring us or check the trunk-live email
- Dial your mobile to confirm Caller ID; ring your DDI from a mobile to confirm inbound
If it won't register
- Most common Htek mistake: the Account isn't bound to the Profile — re-check the Profile selector on Account → Basic
- Wrong SIP User ID / Authenticate Password — re-check against the trunk email
- Primary SIP Server must be
sip.numbergroup.comexactly - Outbound UDP 5060 blocked on your network firewall
- Outbound rejected with 403: your Default CLI on the trunk isn't one of your DDIs — fix on the trunk
Set fraud caps before going live
A single desk phone should never place more than 1–2 simultaneous calls. Ask us to set Fraud Detection Simultaneous Calls to 2 and a sensible Daily Spend ceiling. See our telecom fraud guide.
Phones at supplier cost
Members get Grandstream desk phones at our distributor price (£28 – £83 ex-VAT), and we'll provision an Htek, Yealink or Snom you already own at no extra charge.