SIP Trunking for Your Existing PBX
SIP Trunking for Your Existing PBX
Get reliable business calling without replacing your phone system. Keep your PBX and internet provider, control channels and numbers online, and start with a free account.
- Free SIP trunk account in minutes
- Compatible with SIP-enabled PBX systems, including 3CX
- Self-service control for numbers and channels
- US48 and Canada calling included
What to compare in a SIP trunk provider
The right choice should fit your environment today and give you control as your calling needs change.
Control without complexity
Manage channels, trunks, telephone numbers, billing, and call detail records from one self-service control panel.
Built around your setup
Keep your SIP-enabled PBX, softphones, gateways, and existing internet connection. No forced equipment swap.
Provision when ready
Start with a free account, validate your configuration, then add channels and numbers as business demand changes.
Predictable SIP channel pricing.
Choose capacity around your concurrent calls, then scale it up or down without a long-term contract.
- No SIP trunk setup fee
- Unlimited calling to the US48 and Canada
- Manage service changes online
The SIP.US Control Panel gives me all the tools I need to add, change and delete phone numbers. I can order all the DIDs I need and set them up instantly.
Colin Cook · Thimble River
See if SIP.US is right for your PBX.
Create a free account and test your configuration with the system you already use.