Configuring Calls2teams for use with Dial 9 SIP trunks

This guide allows you to configure a Calls2teams instance to connect your Dial 9 SIP trunking account through to Microsoft Teams.

Configuring the SIP Trunk

To get started in Calls2teams, you'll need to configure a new Custom Trunk, and set the Country to United Kingdom.

Add your Dial 9 numbers within the Trunk Number Ranges (if you have a single number, just add that number on its own), then enter individual numbers as service numbers in +E164 format, i.e. +443300880900.

Enter sip.dial9.co.uk (or your Partner domain if configuring a SIP trunk within your Dial 9 Partner service) as both the SIP Domain and SIP Proxy, select Static IPs as the Authentication Type then enter the IP address advised within Trunking -> SIP Servers in Dial 9 Connect, as the IP Address under Trunk Source IPs.

Configuring the Calling Policy

Within the Calling Policy, set the Protocol to UDP, Propogate Refer to Teams handles transfers, Suppress Contact Data Param as No, then Encrypt Media to No.

Finally, set E164 Number Format to E164 without +, From header to Trunk Caller Id and P-Asserted-Identity Header to Not Present.

At the bottom of this section, you'll be advised of two Current SBC IPs - these need to be added to Dial 9 as outbound trunks. You will also be shown an SRV hostname, this needs to be added as your SIP server, and any SIP URLs require numbers to be entered in +E164 format.

An example SIP URL would therefore look like +443300880900@123123123123123.call2teams.com.

Further information on setting up the connections within Dial 9 can be found in our Setting up a SIP trunk guide.