SF Trunk
SF Trunk is Superfone's SIP trunking product. It connects your own phone system to the Indian phone network. That can be an IP PBX, an SBC, a softphone or a voice AI stack.
- Inbound (origination). Someone calls one of your Superfone numbers. We send the call to your SIP server.
- Outbound (termination). Your SIP server sends a call to us. We put it on the Indian phone network.
You keep your own call logic, agents and AI. Superfone supplies the numbers, the carrier connection, recording, call records and billing from your existing wallet.
How it works
Each trunk gets its own SIP address, a fully qualified domain name (FQDN) of this form:
<label>.sft.superfone.co.in
The label is an eight-character lowercase code generated when the trunk is created. It never changes. The FQDN identifies your trunk, and your PBX sends outbound calls to it.
The flow:
- A trunk is created for your account, and it is active straight away.
- You attach one or more of your Superfone numbers to the trunk and give us the SIP host and port of your server.
- A call to an attached number is delivered to your server.
- Your server sends outbound calls to your trunk FQDN, and we route them to the Indian phone network.
Who it is for
- Teams running their own IP PBX or SBC, such as Asterisk, FreeSWITCH or a hardware SBC, that want Indian numbers and Indian PSTN access.
- Voice AI platforms and in-house AI agents that speak SIP and need a real Indian number to call from and be called on.
- Existing Superfone customers who want calls on their Superfone numbers to land in their own system instead of the Superfone app.
If you would rather control calls over HTTP and WebSocket than run a SIP server, use SFVoPI instead.
At a glance
| Today | |
|---|---|
| Trunk address | <label>.sft.superfone.co.in, one per trunk |
| Directions | Inbound (to your SIP server) and outbound (from your SIP server) |
| Destinations | Indian phone numbers only |
| Codecs | G.711 A-law (PCMA) and G.711 µ-law (PCMU). Always offer PCMA |
| Transport | SIP over UDP or TCP, port 5060 |
| Numbers | Many Superfone numbers per trunk; each number on one trunk or app at a time |
| Security | Your trunk FQDN identifies you. Username/password authentication is coming soon |
| Capacity | Calls per second (CPS) and concurrent calls for your organisation, set by Superfone to match what you bought. Optional lower limits per trunk, set by you |
| Billing | Calls are charged to your Superfone wallet. No separate charge for the trunk or its channels |
| Recording | Both directions. Set per trunk, or left to follow the call recording setting of your Superfone number |
| Maximum call length | One hour |
Organisation call limits ship with the org-limits release.
For the full list, including what is not available yet, see Supported today and coming soon.
Next Steps
- Getting Started: get a trunk, plus the codecs, SIP methods and network details your PBX needs
- Supported today and coming soon: what works now and what is on the roadmap
- Inbound calls: receive calls for your numbers on your SIP server
- Outbound calls: place calls to Indian numbers through your trunk
- Call transfer to Superfone app: transfer a call to a Superfone app user with
REFER - Limits and billing: CPS, concurrency, the wallet and recording
- Troubleshooting: why a call was refused
- FAQ: common questions from teams moving from another SIP trunk provider
Support
Email hello@superfone.in with SF Trunk in the subject.