Connect Flowroute SIP trunk to SessionPBX

Flowroute, now part of BCM One, supplies US numbers and outbound calling over SIP. Flowroute sends incoming calls to a host address, and for outbound calls offers SIP digest authentication or IP authentication. SessionPBX uses digest authentication for outbound, so you add two trunks: one that receives Flowroute’s calls and one that sends your outbound calls.

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

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

Before you start

In the Flowroute Manage portal, open Interconnection > Registration and note:

• your Tech Prefix, an 8-digit number that’s also your SIP username
• your SIP password
• the Point of Presence (PoP) you’ll use

Flowroute’s PoPs are:

Flowroute supports SIP over UDP or TCP. It doesn’t list TLS, so use UDP.

Flowroute’s IP authentication needs your Tech Prefix added in front of every dialled number. SessionPBX doesn’t add prefixes to dialled numbers, so use digest authentication for outbound calls, as below.

SessionPBX addresses for Flowroute

Give Flowroute 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 Flowroute can use UDP, TCP or TLS on whatever port Flowroute specifies.

Part 1: Inbound calls

In Flowroute: create an inbound route

1. Open Interconnection > Inbound Routes.
2. Add a route with Route Type set to Host, and enter your region’s address with the port, for example us.sip.sessiontalk.io:5060.
3. Set Edge strategy to the PoP nearest your SessionPBX region.
4. On the DIDs page, set each number to use this route.

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 Flowroute inbound and choose Generic carrier (IP authentication).
3. Connection: set Host to your PoP’s SIP proxy, for example us-east-va.sip.flowroute.com, Port to 5060 and Transport to UDP. Set Direction to Inbound only.
4. Authentication: keep By our IP address. Under Carrier IP addresses, list the signalling ranges for every Flowroute PoP in the table above, one per line. Flowroute fails over to other PoPs if your preferred one is unavailable.
5. Inbound: list your Flowroute numbers in international format, for example +12066418000. 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

1. On SIP trunks, select Add trunk again.
2. Provider: name it Flowroute outbound and choose Generic carrier (username and password).
3. Connection: set Host to your PoP’s SIP proxy, Port to 5060 and Transport to UDP. Set Direction to Outbound only.
4. Authentication: choose Username and password. Enter your Tech Prefix as the username and your SIP password. Leave Auth realm and From domain blank.
5. Turn Register to this carrier off. Your incoming calls arrive on the inbound trunk instead. 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 one of your Flowroute numbers. Flowroute reads caller ID from P-Asserted-Identity, then Remote-Party-ID, then From, so the default From header only works.
   • Under Additional gateways, you can add a second PoP as a backup, for example us-west-or.sip.flowroute.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.
7. Select Create trunk.

Flowroute needs every number in E.164 format, including US numbers. SessionPBX sends numbers that way.

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 Flowroute in international format.

Test the trunk

1. Call one of your Flowroute 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

• Flowroute: Service guide – technical specifications 
• Flowroute: General PBX or phone system setup guide 
• Flowroute: Configure an inbound route with your preferred PoP 
• Flowroute: Changes to edge proxy/PoP configurations