Connect DIDWW SIP trunk to SessionPBX

DIDWW supplies phone numbers in many countries, including UK geographic and mobile numbers, and outbound calling. DIDWW keeps inbound and outbound service separate, each with its own trunk and hostnames, so in SessionPBX you add two trunks: one that receives DIDWW’s calls, and one that sends your outbound calls to DIDWW.

You bring your own DIDWW account, numbers and caller ID. SessionPBX doesn’t supply DIDWW service.

About this guide. The DIDWW settings on this page were checked against DIDWW’s published documentation on 19 October 2026. The SessionPBX field names come from the Add SIP trunk wizard in the product. If DIDWW shows a different value in your account, use theirs.

Before you start

• A DIDWW account with at least one number
• Outbound service enabled on the account. DIDWW has to approve outbound before you can create an outbound trunk.
• Your SessionPBX region’s address, from the table below

SessionPBX addresses for DIDWW

Give DIDWW the address for the region your workspace is hosted in. If you’re not sure which region that is, email support@sessiontalk.co.uk.

SessionPBX accepts calls from carriers on UDP port 5060 or TLS port 5061. TCP isn’t accepted for incoming calls. Calls that SessionPBX sends to DIDWW can use UDP, TCP or TLS on whatever port DIDWW specifies.

Part 1: Inbound calls

In DIDWW: create the inbound trunk

1. In the DIDWW User Panel, open Voice > Inbound Trunks and create a new SIP trunk.
2. Set Type to Static Endpoint.
3. Set the user part of the Request-URI to {DID}, so the dialled number reaches SessionPBX.
4. Set Host to your region’s hostname, for example uk.sip.sessiontalk.io.
5. Set Transport to UDP with port 5060, or TLS with port 5061. Don’t use TCP.
6. Leave SRTP Mode off, and DTMF send and receive on RFC 2833.
7. Leave Authorization off.
8. Assign your numbers to this trunk.

In SessionPBX: add the inbound trunk

1. Open the SessionPBX project, select Call Routing, and on SIP trunks select Add trunk.

2. Provider: name it DIDWW inbound and choose Generic carrier (IP authentication).

3. Connection: set Host to sip.didww.com, and Port and Transport to the same values you chose on DIDWW’s trunk. Set Direction to Inbound only.

4. Authentication: keep By our IP address. Under Carrier IP addresses, list all of DIDWW’s Static Endpoint signalling addresses, one per line:

   46.19.209.14
   46.19.210.14
   46.19.212.14
   46.19.213.14
   46.19.214.14
   46.19.215.14
   185.238.173.14

   DIDWW can deliver calls from any of its sites, so list them all.

5. Inbound: list your DIDWW numbers in international format, for example +442071234567. DIDWW sends numbers without the +; SessionPBX treats them as the same number. Once calls arrive, you can turn on Refuse unknown numbers. List your numbers on this inbound trunk only. Don’t add them to the outbound trunk: a number listed on two trunks belongs only to the trunk saved last.

6. Select Create trunk.

Part 2: Outbound calls

In DIDWW: create the outbound trunk

1. Open Voice > Outbound Trunks and create a new trunk.
2. Choose credential authentication. If DIDWW asks for allowed SIP IP addresses, enter your SessionPBX region’s IP address from the table above.
3. Under the CLI settings, allow the DIDWW numbers you’ll use as caller ID.
4. Choose the destinations you want to allow, and set capacity and daily limits as a safeguard against fraud.
5. Save the trunk, then view its SIP username and password.

In SessionPBX: add the outbound trunk

1. On SIP trunks, select Add trunk again.

2. Provider: name it DIDWW outbound and choose Generic carrier (username and password).

3. Connection: set Host to the DIDWW outbound endpoint nearest your region:

   SessionPBX region	DIDWW outbound endpoint
   London	ams.eu.out.didww.com
   New York	nyc.us.out.didww.com
   Singapore	sg.out.didww.com

   Use port 5060 with UDP or TCP, or port 5061 with TLS. Set Direction to Outbound only.

4. Authentication: choose Username and password and enter the outbound trunk’s credentials. Set Auth realm to out.didww.com. Leave From domain blank.

5. Turn Register to this carrier off. DIDWW doesn’t need registration for outbound calls. Register to this carrier is on by default for Username and password, so check that it shows off before you continue. Leave Inbound numbers empty on this trunk. Your numbers belong on the inbound trunk only.

6. Outbound: set Caller ID to a DIDWW number allowed in the trunk’s CLI settings. Leave Assert caller ID in on From header only unless DIDWW asks otherwise.

7. Under Additional gateways, you can add a second DIDWW endpoint as a backup, for example fra.eu.out.didww.com:5060/udp 10. Give a backup gateway priority 10. A lower number wins, so calls use the trunk’s main host (priority 0) first and move to the backup only if the main host stops answering. A backup left at priority 0 shares calls with the main host instead.

8. Select Create trunk.

Do not send outbound calls to sip.didww.com. That host is for inbound service only.

Route your numbers

On Call Routing, use Inbound number routing to choose where each number rings: everyone, a team member, a ring group, a call queue or a call flow. See Phone Numbers & Outbound Calls.

Allow members to call out

Outbound calling is off for new members. Open Team Members, edit the member, turn on Outbound PSTN under Access & features, and select Save member.

Members can dial numbers in international format, such as +447700900123. SessionPBX sends the number to DIDWW in international format.

Test the trunk

1. Call one of your DIDWW numbers from an outside phone and check that the right destination rings.
2. With Outbound PSTN on for one member, call a public number. Check that audio works both ways and that the called phone shows the caller ID you expect.
3. If you call into an IVR, check that key presses work. SessionPBX sends and receives key presses as RFC 2833 telephone events.

If calls fail, email support@sessiontalk.co.uk with the time of the call, the number you called from and the number you called.

Sources

• DIDWW: SIP connectivity reference (inbound trunks) 
• DIDWW: Creating a new SIP trunk 
• DIDWW: Outbound SIP information 
• DIDWW: Create an outbound trunk 
• DIDWW: Outbound authentication and security