We have been working on this issue with our vendor for months to no avail. We have an FXT with a PRI. All 23 channels on the PRI should be 2 way. However, if more than 8 outbound calls are placed, all phones get a "No Lines Available" message.
The vendor has assured me that the trunk group is larger than 8 trunks.
Here's what we've done:
*PRI testing with both carrier & CPE on site.
*Swapped the PRI card
*Swapped the PRI card slot
*Collected/analyzed errors
*Had a 2nd vendor come in and examine the programming.
*Escalated to Comdial.

Right now, we're talking about trying to budget for a whole new PBX. Any thoughts would be appreciated.