Connect your phone number via SIP-Trunk

1. Forwards calls to a SIP address of your choice (key requirement) Your provider must allow you to enter our SIP address as the destination for incoming calls, including the port and transport protocol, for example sip:voice.your-company.com:5061; transport=tls. You can find the address for your channel in the phone channel settings. This setting is commonly called an Origination URL or “Termination to a custom SIP address.” Calls are delivered over IPv4. 2. Encrypts the connection Your provider must establish calls using SIP/TLS (port 5061) and encrypt the audio using SRTP. Unencrypted calls will be rejected. In Twilio, this setting is called Secure Trunking. 3. Does not require us to register Some older connections require the receiving system to register with the provider first. Lime Connect cannot do this, so registration-based trunks are not supported. 4. Allows you to secure the connection Only your provider should be able to deliver calls to your channel. To ensure this, configure at least one of the following options in the phone channel settings: • Option 1 – Username and password: Set a username and password in the phone channel and configure the same credentials with your provider. We request them with every call, and the provider must be able to respond using SIP digest authentication. Your provider will usually call this setting SIP credentials or Digest authentication. Both the username and password are required. Twilio does not support this option; use Option 2 instead. • Option 2 – Allowed IP addresses: In the phone channel, enter the public IP addresses from which your provider delivers calls. Ask your provider for its outbound SIP servers, often called signaling IPs. Calls from all other addresses will be rejected. Each entry must be either a single address (203.0.113.4) or a network address in CIDR notation (198.51.100.0/24). Ranges cannot be broader than /8, and catch-all entries such as 0.0.0.0/0 are rejected. This option requires your provider to send calls from fixed, documented addresses. Otherwise, use Option 1. Note: Without this protection, the connection would accept calls from anyone who knows the SIP address. For this reason, your phone number cannot be activated until one of these options has been configured. You can also use both options together. 5. Transmits the phone numbers Your provider must send the number dialed by the caller in international format (for example, +49221...) so that we can route the call to the correct channel. Without it, the call will not be delivered. The caller’s phone number must also be transmitted, although withheld caller ID is supported.