PRI Circuit on New Server Not Coming Up: Troubleshooting Guide

We’re encountering an issue where a new server isn’t bringing up the PRI circuit. The system is showing yellow alarms, and consequently, incoming and outgoing calls are failing. This guide outlines the problem and steps taken to diagnose it, aiming to provide solutions for similar Server Pri issues.

The setup involves replacing an older FreePBX 2 system with a new FreePBX 14 server. Both systems utilize a Digium TE110P card for PRI connectivity. The card jumper is confirmed to be set for T1 operation, and configurations are aligned with the PRI provider’s specifications. These settings include ESF/B8ZS framing, pri_cpe National ISDN 2 protocol, Clock Source 0, and Line Build Out 0db for short cable runs.

Despite these configurations, the DAHDI service status reveals persistent yellow alarms across all spans, indicating a problem with the PRI circuit initialization.

**[root@freepbx ~]# service dahdi status**
Span 1: WCT1/0 "Digium Wildcard TE110P T1/E1 Card 0" (MASTER) ESF/B8ZS YELLOW
1 PRI Clear (In use) YELLOW
2 PRI Clear (In use) YELLOW
3 PRI Clear (In use) YELLOW
4 PRI Clear (In use) YELLOW
5 PRI Clear (In use) YELLOW
6 PRI Clear (In use) YELLOW
7 PRI Clear (In use) YELLOW
8 PRI Clear (In use) YELLOW
9 PRI Clear (In use) YELLOW
10 PRI Clear (In use) YELLOW
11 PRI Clear (In use) YELLOW
12 PRI Clear (In use) YELLOW
13 PRI Clear (In use) YELLOW
14 PRI Clear (In use) YELLOW
15 PRI Clear (In use) YELLOW
16 PRI Clear (In use) YELLOW
17 PRI Clear (In use) YELLOW
18 PRI Clear (In use) YELLOW
19 PRI Clear (In use) YELLOW
20 PRI Clear (In use) YELLOW
21 PRI Clear (In use) YELLOW
22 PRI Clear (In use) YELLOW
23 PRI Clear (In use) YELLOW
24 PRI HDLCFCS (In use) YELLOW

Further hardware checks confirm the Digium TE110P card is recognized by the system:

**[root@freepbx ~]# dahdi_hardware**
pci:0000:05:00.0 wcte11xp+ e159:0001 Digium Wildcard TE110P T1/E1 Board

DAHDI scan results also indicate the card is active and configured, but still reports alarms:

**[root@freepbx ~]# dahdi_scan**
[1]
    active=yes
    alarms=YELLOW
    description=Digium Wildcard TE110P T1/E1 Card 0
    name=WCT1/0
    manufacturer=Digium
    devicetype=Digium Wildcard TE110P T1/E1
    location=PCI Bus 05 Slot 01
    basechan=1
    totchans=24
    irq=0
    type=digital-T1
    syncsrc=0
    lbo=0 db (CSU)/0-133 feet (DSX-1)
    coding_opts=B8ZS,AMI
    framing_opts=ESF,D4
    coding=B8ZS
    framing=ESF

Finally, the Asterisk DAHDI status echoes the alarm state:

Connected to Asterisk 13.19.1 currently running on freepbx (pid = 22153)
**freepbx*CLI> dahdi show status**
Description                    Alarms   IRQ   bpviol CRC    Fra Codi Options              LBO
Digium Wildcard TE110P T1/E1 Card 0 YELLOW 0     0      0      ESF  B8ZS 0 db (CSU)/0-133 feet (DSX-1)

The consistent yellow alarms across DAHDI status and scans suggest a potential issue with the physical connection, clock synchronization, or configuration mismatch with the PRI provider despite initial settings appearing correct. Further investigation should focus on:

Verifying physical cable connections: Ensure the T1/PRI cable is securely connected to both the server card and the telco demarcation point.
Double-checking PRI provider settings: Confirm all configuration parameters (framing, coding, clocking, line build out) with the service provider to rule out any discrepancies.
Clock source synchronization: While Clock Source 0 is set, it’s crucial to ensure the card is properly synchronizing with the network clock. If possible, testing with Clock Source 1 (line) might be beneficial for troubleshooting.
Hardware compatibility: Although the card model is the same, ensure compatibility with FreePBX 14 and the underlying operating system. Check for any driver updates or specific configuration requirements for this environment.

Addressing these points systematically will help pinpoint the root cause of the PRI circuit issue and restore call functionality on the new server.