Connect AI voice platforms

Before you start, you need:

• An active SF Trunk and its FQDN ({{LABEL}}.sft.superfone.co.in). See Getting Started.
• At least one Superfone number attached to the trunk. See Inbound calls.
• If your platform filters by source address, the addresses in Network addresses to allowlist.

Connecting a standards-based PBX or SBC instead? See the example configurations on the Outbound Calls page.

Treat your FQDN like a password

Anyone who knows your FQDN and one of your attached numbers can place calls on your trunk. Keep it out of public config, screenshots and support tickets. See Outbound calls.

ElevenLabs Agents

1. Go to Deploy > Phone Numbers > Import a number, and select SIP Trunk.
2. Name it (for example, "Superfone") and enter the phone number — one of your numbers attached to the trunk, in E.164, for example {{YOUR_SUPERFONE_NUMBER}}.
3. Inbound config: set Media Encryption to Disabled.
4. Outbound config — Address: your trunk FQDN, {{LABEL}}.sft.superfone.co.in.
5. Outbound config: set Media Encryption to Disabled.
6. Outbound config — Codecs: select only PCMA and PCMU. Unselect G.722 — SF Trunk does not support it.
7. Transport: UDP (default). If you hit connection issues, try TCP on both this setting and the matching Superfone trunk setting below. SF Trunk does not support TLS — do not select it here.
8. Save. This creates the connection between your ElevenLabs agent and your Superfone trunk.
9. Open the phone number again and assign an agent to handle inbound calls. Use the Outbound call button there to test — always dial in full E.164, +91{{NUMBER}}.

On your Superfone trunk, set:

Field	Value
customer_sip_host	sip.rtc.elevenlabs.io
customer_sip_port	5060
customer_sip_transport	udp (try tcp if you have issues — match whatever you set in step 7)

Vapi

Vapi's gateway form needs a numeric IP for any gateway with inbound calls enabled, and accepts a domain only when inbound is off. Set up two separate gateways:

Gateway #1 — inbound (calls from Superfone to Vapi)

Field	Value
IP Address / Domain	Superfone's SIP signalling address — see Network addresses to allowlist
Port	5060
Netmask	32
Outbound Protocol	UDP
Allow inbound calls	✅
Allow outbound calls	⬜

Gateway #2 — outbound (calls from Vapi to your trunk)

Field	Value
IP Address / Domain	{{LABEL}}.sft.superfone.co.in
Port	5060
Netmask	32
Outbound Protocol	UDP
Allow inbound calls	⬜
Allow outbound calls	✅

On the phone number's Advanced Settings, turn on "Enable leading plus for outbound calls" — SF Trunk requires E.164 numbers with a leading +, and calls will be refused with 400 Bad Request without this.

If Vapi also filters inbound media by address, allow Superfone's media (RTP) address and port range from Network addresses to allowlist.

On your Superfone trunk, set:

Field	Value
customer_sip_host	44.229.228.186 (US region) or 63.182.83.170 (EU region)
customer_sip_port	5060
customer_sip_transport	udp

Bolna

In Bolna's Create/Edit SIP Trunk wizard:

1. Basics: platform Custom.
2. Authentication: auth type IP-Based. Enter Superfone's SIP signalling address — see Network addresses to allowlist — as the trusted source IP.
3. Gateways: address = your trunk FQDN, {{LABEL}}.sft.superfone.co.in, port 5060.
4. Advanced:

Setting	Value
Allowed Codecs	ulaw,alaw
Disallowed Codecs	all
Transport Protocol	UDP
SIP OPTIONS Ping Interval	60
RTP Symmetric	On
Force rport	On
Enable Inbound Calling	On
Prepend + to Outbound Numbers	On
Trunk Active	On

5. Review and save.

If Bolna also filters inbound media by address, allow Superfone's media (RTP) address and port range from Network addresses to allowlist.

On your Superfone trunk, set:

Field	Value
customer_sip_host	sip.bolna.ai
customer_sip_port	5060
customer_sip_transport	udp

Retell

1. Go to Phone Numbers, and import or add a number.
2. Enter your Superfone number, in E.164, for example {{YOUR_SUPERFONE_NUMBER}}.
3. Termination URI: your trunk FQDN, {{LABEL}}.sft.superfone.co.in. This is the address Retell sends calls to when your number places an outbound call.
4. Click Test SIP Connection.
5. Once connected, open the number and assign an agent to handle inbound calls.

On your Superfone trunk, set:

Field	Value
customer_sip_host	sip.retellai.com
customer_sip_port	5060
customer_sip_transport	tcp (Retell's recommended transport; udp also works)

No IP whitelisting needed

Retell routes inbound calls by the dialled number, not by source IP, so there is nothing to whitelist on Retell's side. Superfone has no IP-ACL setting on the trunk either — this integration needs no IP list in either direction.

Next Steps

• Troubleshooting: fix a connection that isn't working
• Limits and billing: wallet balance and capacity limits