Troubleshooting

Common PoE board issues and solutions

  5 minute read  

This guide covers common issues with the Interceptor PoE Board and their solutions.

Detection Issues

PoE board not detected (/proc/pse missing)

Symptoms: The /proc/pse file doesn’t exist.

Solutions:

  1. Check OS version - Requires exaviz OS 2025-05-01 or newer:

    cat /etc/os-release

  2. Check FFC cable - Ensure the 40-pin cable is properly seated and locked at both ends

  3. Check 48V power - Verify the VOITA converter is powered and connected to J1

  4. Check driver loading:

    dmesg | grep -i "ip808\|poe"
lsmod | grep ip808

  5. Reboot after verifying connections

Board detected but ports don’t work

Symptoms: /proc/pse exists but ports show errors or won’t enable.

Solutions:

  1. Check power supply - 48V from VOITA converter:

    • Verify converter input (12V from PSU)
    • Check terminal block connections on PoE board

  2. Check for fault status:

    cat /proc/pse

  3. Reset the board by power-cycling the system

Power Issues

Port shows “fault” status

Symptoms: Port status shows “fault” in /proc/pse.

Possible Causes:

  • Short circuit in cable or device
  • Overcurrent (device drawing too much power)
  • Non-PoE device connected
  • Cable wiring fault

Solutions:

  1. Disconnect the device from the port
  2. Reset the port:
    echo "reset-port 0 <port>" > /proc/pse
  3. Check the cable for damage
  4. Verify the device is PoE-compatible
  5. Try a different port

Device not receiving power

Symptoms: PoE device doesn’t power on, but port shows “power on” or “searching”.

Solutions:

  1. Verify device is PoE-capable - Check device specs for 802.3af or 802.3at support

  2. Check cable:

    • Use Cat5e or better
    • Ensure all 8 wires are connected (PoE uses pins 1,2,3,6 for data and 4,5,7,8 for power)
    • Try a different cable

  3. Check port status:

    cat /proc/pse | grep "Port <number>"

  4. Try a different port to isolate hardware issues

  5. Check power budget - You may have exceeded the total available power

Intermittent power delivery

Symptoms: Device powers on then off randomly.

Solutions:

  1. Check total power budget:

    cat /proc/pse | grep "power on"

    Calculate total watts and compare to your PSU capacity

  2. Check PSU 12V stability - The VOITA converter needs stable 12V input

  3. Reseat FFC cables - A loose connection can cause intermittent issues

  4. Check for thermal issues - Ensure adequate airflow around the PoE board

Multiple ports failing simultaneously

Symptoms: Several ports stop working at once.

Likely Cause: Power supply overload or 48V power issue.

Solutions:

  1. Reduce load - Disable some ports and test:

    echo "disable-port 0 7" > /proc/pse
echo "disable-port 0 6" > /proc/pse

  2. Check VOITA converter - Verify output voltage (should be ~48V)

  3. Check PSU 12V rail - May be sagging under load

  4. Upgrade PSU if power budget is exceeded

Connection Issues

FFC cable problems

Symptoms: Intermittent detection, random port failures.

Solutions:

  1. Reseat the cable:

    • Power off system
    • Unlock clips on both connectors
    • Remove cable
    • Inspect for damage
    • Reinsert and lock

  2. Check cable orientation:

    • Blue reinforcement tape faces up (toward clips)
    • Contacts face down (toward PCB)

  3. Replace cable if damaged

Network connectivity issues on PoE ports

Symptoms: Power works but no network connection.

Solutions:

  1. Check link LEDs on the PoE board ports

  2. Verify cable - Try with a known-good cable

  3. Check device configuration - Ensure device is configured for DHCP or has correct static IP

  4. Remember PoE ports are 100Mbps - Some devices may expect Gigabit

LED Indicators

Understanding port LEDs

LED StateMeaning
Green solidLink established
Green blinkingNetwork activity
Amber solidPoE power active
No LEDsNo link or power

No LEDs on any port

Possible Causes:

  • 48V power not connected
  • FFC cable not connected
  • Board not detected by OS

Solutions:

  1. Check all power connections
  2. Verify FFC cable is seated
  3. Check /proc/pse exists

Meaning: Network link works but PoE is not delivering power.

Solutions:

  1. Enable the port:
    echo "enable-port 0 <port>" > /proc/pse
  2. Device may not be PoE-capable
  3. Check cable (all 8 wires needed for PoE)

Software Issues

Permission denied writing to /proc/pse

Solution: Use root privileges:

# Method 1: Use tee
echo "enable-port 0 0" | sudo tee /proc/pse

# Method 2: Run as root
sudo -i
echo "enable-port 0 0" > /proc/pse
exit

Commands not working

Symptoms: Writing to /proc/pse doesn’t change port status.

Solutions:

  1. Check syntax:

    # Correct
echo "enable-port 0 0" > /proc/pse

# Wrong (missing hyphen)
echo "enable port 0 0" > /proc/pse

  2. Check board/port numbers - Board is 0-1, port is 0-7

  3. Check driver status:

    dmesg | tail -20

Diagnostic Commands

Full system diagnostic

# OS version
cat /etc/os-release

# PoE status
cat /proc/pse

# Kernel messages
dmesg | grep -i "poe\|ip808\|pse"

# Module status
lsmod | grep ip808

# Network interfaces
ip link show

# USB devices (includes some PoE controllers)
lsusb

Generate support information

#!/bin/bash
echo "=== System Info ===" > poe-diagnostic.txt
uname -a >> poe-diagnostic.txt
cat /etc/os-release >> poe-diagnostic.txt

echo -e "\n=== PoE Status ===" >> poe-diagnostic.txt
cat /proc/pse >> poe-diagnostic.txt 2>&1 || echo "/proc/pse not found" >> poe-diagnostic.txt

echo -e "\n=== Kernel Messages ===" >> poe-diagnostic.txt
dmesg | grep -i "poe\|ip808\|pse" >> poe-diagnostic.txt

echo -e "\n=== Loaded Modules ===" >> poe-diagnostic.txt
lsmod | grep -i "ip808\|poe" >> poe-diagnostic.txt

echo "Diagnostic saved to poe-diagnostic.txt"

Getting More Help

If the above solutions don’t resolve your issue:

  1. Run the diagnostic script above
  2. Note the specific symptoms and when they occur
  3. Contact info@exaviz.com with:
    • Diagnostic output
    • Description of the issue
    • Steps you’ve already tried

Last modified December 30, 2025