SIP trunking
SIP trunking for your PBX: keep it, plug in our numbers
Connect 3CX, FreePBX, Asterisk or Yeastar to local, national and mobile numbers in 12 countries — encrypted, billed per call, with no channel licenses and no contract.
Compatibility
Settings for the PBX you already run
Any standards-compliant SIP PBX works. Here is what to pick in the most common ones.
| PBX | Trunk type | Authentication | Transport |
|---|---|---|---|
| 3CX | Generic SIP trunk | Registration | TLS 5061 |
| FreePBX | PJSIP trunk | Registration or IP | TLS 5061 |
| Asterisk | pjsip.conf endpoint | Registration or IP | TLS 5061 |
| Yeastar P-Series | Register trunk | Registration | TLS 5061 |
| FusionPBX | Gateway | Registration | TLS 5061 |
| Grandstream UCM | VoIP trunk | Registration | TLS 5061 or UDP 5060 |
Inbound calls arrive in E.164 format (+13055550142), so one dial plan handles every country.
Technical details
What the trunk supports
Open standards your PBX already speaks — nothing proprietary to install.
Encrypted by default
TLS 1.2+ signalling and SRTP media. UDP and TCP on 5060 for older equipment.
HD voice
Opus and G.722 wideband, G.711 µ-law and A-law everywhere.
Reliable DTMF
RFC 4733 events, so menus and voicemail PINs work on every route.
Any caller ID you own
Present any number on your account, from any country.
Failover
PBX unreachable? Calls go to voicemail, a forward or a hosted call flow.
Spending caps
Daily and monthly limits stop toll fraud before it costs you.
Billing
Pay for numbers and minutes. Nothing else.
No per-channel fee, no minimum commitment: each number costs a one-time $15 activation, then its rental. Numbers renew from your crypto balance; minutes are billed at the rate shown on the rates page.
- Local and national numbers from $4/month, + $15 activation each
- Inbound calls on local numbers included
- Outbound calls at the destination rate, shown before you dial
- Unlimited concurrent calls within your spending caps
- Receipts for every payment, with your billing details
Which PBX systems work with your SIP trunks?
Any standards-compliant SIP PBX: 3CX, FreePBX, Asterisk, Yeastar, FusionPBX, Grandstream UCM and others. Use registration with a username and password, or IP authentication if your PBX has a fixed public address.
How many simultaneous calls can I make?
There is no channel license to buy. Concurrent calls are limited only by the spending caps you set, so a runaway PBX or a compromised extension can’t drain your balance.
Is the connection encrypted?
Yes, if your PBX supports it: signalling over TLS on port 5061 and media over SRTP. Plain UDP or TCP on port 5060 remains available for older equipment.
What happens if my PBX goes offline?
You choose a failover for each number: voicemail, a forward to another phone, or a call flow hosted by us. Calls never hit a dead end.
Can I bring my existing numbers?
Porting a number in usually requires the current owner’s identity documents, which we don’t collect. Rent new numbers in any of our 12 countries and keep your old ones running in parallel during the switch.
Numbers for your PBX in 12 countries
Local and national numbers, live the moment you pay.