🧩 Before you start
The Calls channel must be enabled on your account. If you don't see it, reach out and we'll enable it.
Decide whether you want Darwin to provide a number or to connect your own number.
To activate a new number in a country for the first time, we need the account holder's documents: ID or passport and proof of address.
🔀 The two ways to connect a number
Option 1 — Number provided by Darwin (the simplest)
Darwin obtains and configures a number for you. No telephony infrastructure or provider of your own is required.
Best if: you don't have a number or phone system yet.
What you do: tell us the country and the type of number you need.
What we need: for new countries, the account holder's documents (see Before you start).
We take care of provisioning and configuration.
Option 2 — Your own number via SIP Trunking
Connect a number or phone system you already have (your PBX or telephony provider) to Darwin, without porting or buying a new number.
Best if: you already have numbers in production or your own telephony provider.
It requires some setup on your side; we explain it below.
📞 Connecting your number via SIP Trunking
What is SIP Trunking?
SIP (Session Initiation Protocol) is the industry-standard protocol for making voice calls over the internet. A SIP Trunk is the virtual link that carries calls between your phone system or telephony provider and Darwin using that protocol, with no physical lines involved. This way, calls come in and go out through your current number.
What our SIP Trunk supports
Our SIP Trunk runs on LiveKit, a real-time telephony platform. Here's what it supports:
Call direction: inbound and outbound.
SIP transport: UDP, TCP and TLS.
Audio codecs: G.711 (PCMU / µ-law and PCMA / A-law) and G.722 (HD voice) by default; AMR-WB optional.
DTMF tones: yes (RFC 2833 / RFC 4733), for menus and IVR.
Authentication: by IP range (whitelist) and, optionally, SIP authentication with username and password.
Numbering: E.164 international format.
Note: make sure your phone system or provider supports these options. If you're unsure, reach out and we'll review it with you.
How the connection works
The connection has two parts: what you configure on your side and the information you share with us so we can finalize it.
Step 1 — Configure your phone system (your side)
In your phone system or with your provider, add Darwin's details:
Darwin's SIP URI (inbound): sip:2s6skg9rvt6.sip.livekit.cloud
Darwin's IPs to whitelist: 143.223.88.0/21 and 161.115.160.0/19
With those details:
Add Darwin's SIP URI to your system to route calls to Darwin.
Whitelist Darwin's IPs. This is required if you want Darwin to be able to make outbound calls.
Note: if you're not sure how to do these steps, your telephony provider can help. If in doubt, reach out and we'll guide you.
Step 2 — Share your information with us
To complete the connection from Darwin's side, we need:
Channel name: a descriptive name to identify the connection (e.g. Sales US).
Phone number: in E.164 international format — the + sign, country code and number, with no spaces or dashes (e.g. +15551234567).
Your SIP URI: your phone system's SIP URI. Important: enter it without the
sip:prefix.Do you need to receive inbound calls? Let us know if the number will receive calls in addition to placing them.
Does your provider require SIP authentication? Only if your provider requires authentication, share the username and password. Otherwise, it's not needed.
Step 3 — We finalize the connection
With that information, the Darwin team completes the setup and we run a test call to confirm everything works. Done! 🎉
ℹ️ Good to know
E.164 format: always starts with + , followed by the country code and number, with no spaces, dashes or parentheses.
Documents for new countries: when activating a number in a country for the first time, we ask for the account holder's ID/passport and proof of address.
Questions about the connection? Reach out via the support chat and we'll help you get it running.