Connect a Gigaset N-series DECT phone to a NumberGroup SIP trunk
Map your NumberGroup SIP trunk credentials onto a Gigaset N530/N670/N870 IP PRO DECT base — create a provider profile, add a SIP account, then assign it to a handset. Mapping table plus Gigaset's own Admin Master guide.
This registers a Gigaset N-series DECT base (N530 IP PRO single-cell, N670 / N870 IP PRO multicell) to a NumberGroup SIP trunk. DECT differs from a desk phone: you set the server up once as a provider profile, create a SIP account for the credentials, then assign that account to a handset— so there's one extra step the desk-phone guides don't have.
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 on the handset screen.
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
Gigaset owns the click-path and keeps it current — the table below maps each NumberGroup value to its exact field, across the three layers an N-series base splits config into: the Provider or PBX profile (the server), the SIP account (the credentials), and the SIP account assignment (which binds the account to a handset).
Browse to the base's IP from a computer on the same LAN and log in to the web configurator as admin. Config spans three areas: Settings → Provider or PBX profiles (create the connection — Domain, proxy, port), then Settings → SIP accounts → Administration (add the account credentials and pick the profile), then Settings → SIP accounts → Assignments (give a handset the account for Send and Receive).
Full navigation is in the manufacturer's own guide: Gigaset N530 IP PRO Admin Master (hosted by ProVu). 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 | Gigaset N-series field |
|---|---|
| sip.numbergroup.com | Domain (Provider or PBX profiles → General provider data) — mandatory for SIP registration |
| sip.numbergroup.com | Proxy server address (Provider or PBX profiles) |
| 5060 | Proxy server port (Provider or PBX profiles) |
| UDP | Transport protocol (Provider or PBX profiles) |
| T-AAAAAA-NNN | Authentication name (SIP accounts → Personal provider data) |
| your trunk password | Authentication password (SIP accounts → Personal provider data) |
| T-AAAAAA-NNN | Username (SIP accounts → Personal provider data) |
| select profile | VoIP provider (SIP accounts — pick the profile you created) |
| assign to handset | Send + Receive (SIP accounts → Assignments, per Internal Handset) |
Don't skip the last row. If you configure the profile and SIP account but miss SIP accounts → Assignments, the account registers fine but no handset can place or receive calls on it — this is the single most common N-series setup mistake. Each handset takes one account for Send (outgoing) and one or more for Receive (incoming).
Split-field note: the N-series splits Authentication name from Username. On a NumberGroup trunk both take the same value — your T-AAAAAA-NNN. Leave Display name blank unless you want a specific name shown to the called party.
Verify
- On the SIP accounts page, the account shows the green SIP registered indicator
- We can confirm the trunk has registered our side — ring us or check the trunk-live email
- Dial your mobile from the handset to confirm Caller ID; ring your DDI from a mobile to confirm inbound
If it won't work
- Account registered but the handset can't call: you missed SIP accounts → Assignments — give the handset the account for Send and Receive
- Won't register: wrong Authentication name / Authentication password, or Domain not
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 DECT base with a handful of handsets should be capped to your real peak. Ask us to set Fraud Detection Simultaneous Calls and a sensible Daily Spend ceiling. See our telecom fraud guide.
Cordless that just works
Members get SIP trunks with no per-channel fee and BT Wholesale call rates passed straight through — run your Gigaset handsets across the site on a modern carrier without replacing the kit.