SIP Trunking

Bring your own carrier. Keep your rates.

Register your carrier's SIP trunk with Zoice, attach the phone numbers it owns, and route inbound calls straight to AI agents. Your telephony contract, your DIDs, your negotiated rates — with Zoice running the conversation layer on top.

  • UDP, TCP, or TLS transport with SRTP media encryption
  • Digest credentials or IP-CIDR allowlist authentication
  • DIDs bound to agents for instant inbound routing

Your carrier · Mumbai trunk

sip.yourcarrier.net

BYOC
OPTIONS probe200 OK · reachable
Transport
TLS · port 5061
Auth
Digest (username / password)
Codecs
PCMU · PCMA · opus · G722
SRTP
DTLS-SRTP
DTMF
RFC 2833
Max concurrent
50 calls

SIP passwords are write-only — the API never returns them.

How it works

From carrier trunk to AI agent in four steps

If you can fill in a host, a port, and credentials, you can put an AI agent on your existing telephony — no porting, no parallel numbers.

01

Register your trunk

Point Zoice at your carrier's SIP host and port, choose UDP, TCP, or TLS transport, and authenticate with digest credentials or an IP-CIDR allowlist — INVITEs are accepted only from the source addresses you list. Set the trunk's direction: inbound, outbound, or both.

02

Probe it for real

Every trunk has a test button that sends a genuine SIP OPTIONS probe to your carrier and reports the result — so you know the trunk is reachable before the first production call, not after.

03

Attach DIDs, bind agents

Manage the phone numbers a trunk owns in the DID tab. Bind each DID to an AI agent and inbound calls on that number route to it automatically — no dial-plan scripting.

04

Set guardrails, go live

Order your codec preference (PCMU, PCMA, opus, G722), turn on SRTP media encryption, pick a DTMF mode, and cap concurrent calls below your carrier's contractual channel count for headroom. Choose BYOC or resold billing and start calling.

Capabilities

Carrier-grade controls, dashboard simple

Everything a telecom engineer expects from a trunk — configured from a form, verified with a probe.

Any transport, your call

Trunks register over UDP, TCP, or TLS to any carrier host and port. Direction is per trunk — inbound only, outbound only, or both.

Two authentication modes

Digest auth with username and password, or an IP allowlist of CIDR ranges — INVITEs are accepted only from the source addresses you list. Validation catches misconfigurations before they're saved.

Codec preference order

Rank PCMU, PCMA, opus, and G722 in the order you prefer — the first codec your carrier supports wins the negotiation.

Encrypted media with SRTP

Turn on SRTP via SDES or DTLS-SRTP, both running over TLS signaling, so call audio between Zoice and your carrier is encrypted in transit.

DTMF that fits your carrier

Keypad digits arrive however your carrier sends them: RFC 2833 out-of-band events, SIP INFO messages, or in-band audio.

DID management built in

A dedicated phone-numbers tab lists every DID a trunk owns. Bind a DID to an AI agent and inbound calls on that number route to it automatically.

Real OPTIONS health probes

Each trunk has a one-click test that sends an actual SIP OPTIONS probe to the carrier and reports reachability — not a mock status light.

Write-only credentials

SIP passwords are never returned by the API. When editing a trunk, leaving the password blank keeps the stored secret untouched — rotation is deliberate, never accidental.

Concurrency guardrails

Cap concurrent calls per trunk; the outbound dispatcher rejects new calls at the limit. Set the cap below your carrier's contractual channel count to leave headroom.

BYOC — bring your own carrier

Your carrier rates, our AI

Every trunk parameter, spelled out. If your carrier speaks SIP, Zoice terminates it.

SIP trunk specification

Configured per trunk from the dashboard

DirectionInbound, outbound, or both — per trunk
EndpointAny carrier SIP host and port (default 5060)
TransportUDP · TCP · TLS
AuthenticationDigest (username / password) or IP-CIDR allowlist
Codec preferencePCMU · PCMA · opus · G722 — honored in your order
Media encryptionSRTP via SDES or DTLS-SRTP (requires TLS)
DTMFRFC 2833 · SIP INFO · in-band audio
Concurrent callsPer-trunk cap — dispatcher rejects calls at the limit
BillingBYOC (carrier bills you) or resold
Health checkReal SIP OPTIONS probe, on demand per trunk
Numbers (DIDs)Owned by the trunk, bound to agents for inbound routing
CredentialsWrite-only — passwords never returned by the API

Your carrier rates, our AI

In BYOC mode your carrier keeps billing you directly at your negotiated per-minute rates — Zoice never sits in the money flow for telephony. You pay Zoice for the AI conversation layer only.

No porting, no parallel numbers

Your DIDs stay exactly where they are. Register the trunk, bind each number to an agent, and inbound callers reach an AI on the same numbers they have always dialed.

Resold when you want it

No carrier relationship yet? Flip the trunk to resold billing and Zoice carries the telephony for you — switch to BYOC later without rebuilding anything.

Zoice bills for the AI conversation layer only — see pricing for plans, and the security page for how credentials and call data are protected.

SIP Trunking — Frequently Asked Questions

Terminate SIP straight into an AI agent

Register a trunk, run the OPTIONS probe, bind your DIDs — and the numbers your customers already dial start answering themselves.

ZOICE