Asterisk Configuration Settings for outgoing calls - UK BT ISDN2e BRI

The scenario:

• You’re using Asterisk / FreePBX / Elastix / Trixbox
• You’re attaching to UK BT BRI (ISDN2e) lines
• Incoming BRI calls work
• Outgoing BRI calls don’t work
• When dialling using an outbound route you may hear, “All circuits are busy now” (Elastix you will)

You may see errors such as:

• Ext: 1 Cause: Unallocated (unassigned) number (1), class = Normal Event (0) ]
• “TRUNK Dial failed due to CHANUNAVAIL (hangupcause: 1) - failing through to other trunks”) in new stack

Potential Resolution:

Add to your dhadi-channels.conf the following for each span (we use Xorcom’s Astribank for BRI):

pridialplan=unknown

prilocaldialplan=unknown

Then just gracefully restart asterisk. To wait for an empty call volume, you can use this command in the asterisk terminal:

restart when convenient