Troubleshooting

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. Commands fail with “No such device” error.

Solutions:

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

   cat /etc/os-release | grep VERSION
   

   If older than 2025-05-01, update to a newer OS image. If you’re using standard Raspberry Pi OS instead of Exaviz OS, you’ll need to download and install Exaviz OS.

2. Check FFC cable connection:

   • ⚠️ CRITICAL: Power off system completely before checking or handling FFC cables
   • Moving or unplugging FFC cables while powered can cause them to short, pop, and smoke - permanently destroying them
   • Verify cable is locked at both ends (carrier board J9/J10 and PoE board J2)
   • Check cable orientation:
   • Contacts face up (printing visible on top)
   • Blue reinforcement tape faces down
   • Ensure cable is seated evenly (both sides at same depth)
   • If uneven, remove and reinsert
   • Lock clips securely before powering on

3. Check 48V power:

   • Verify VOITA converter input (12V from PSU) is connected
   • Verify VOITA converter output (48V) is connected to PoE board J1 terminal block
   • Check polarity (+ to +, - to -)
   • Measure voltage at J1 terminal (should be ~48V)

4. Check 3.3V rail stability:

   • If /proc/pse is missing, Linux may have failed to communicate with the IP808AR over I2C
   • This can happen if the 3.3V rail drops too low
   • Check PSU 3.3V rail voltage (should be 3.3V ±5%)
   • Verify PSU is adequate for your configuration (see Power Issues)
   • Low-quality PSUs may not maintain stable 3.3V under load
   • If voltage is low or missing, check converter and PSU connections

5. Check driver loading:

   # Check kernel messages for driver
   dmesg | grep -i "ip808\|poe\|pse"
   
   # Check if module is loaded
   lsmod | grep ip808
   
   # Try loading manually
   sudo modprobe ip808ar
   
   # Check for errors
   dmesg | tail -20
   

6. Check USB devices (IP808AR may appear as USB device):

   lsusb
   

7. For dual PoE boards:

   • Verify both FFC cables are connected (J9 and J10 on carrier)
   • Verify 48V power is connected to at least one board (power is shared via FFC)
   • Check both boards’ J1 terminals if power issues persist

8. Reboot after verifying all connections:

   sudo reboot
   # After reboot, check again
   ls -l /proc/pse
   head -20 /proc/pse
   

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:

   head -20 /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 detecting.

Solutions:

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

2. Check cable (8-wire requirement):

   • Use Cat5e or Cat6 with all 8 wires connected
   • The Interceptor PoE Board uses Mode B power delivery (pins 4, 5, 7, 8)
   • 4-wire cables (pins 1, 2, 3, 6 only) will not work
   • Cables from some NVR systems (Swann, Lorex, etc.) may be 4-wire only
   • Try a different, known-good 8-wire cable
   • See FAQ: Why don’t my existing PoE cables work? for details

3. Check port status:

   head -20 /proc/pse | grep "0-3:"   # Replace 0-3 with your board-port
   

4. Try a different port to isolate hardware issues

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

Long cables not working (voltage drop)

Symptoms: Devices work with short cables (<10ft) but fail with long cables (50ft+). No link light, device doesn’t power on.

Cause: Voltage drop over long Ethernet cables. IEEE 802.3at requires minimum 37V at the device (PD), but voltage drops ~0.2-0.3V per 10ft at typical camera current (0.3-0.5A).

Solutions:

1. Check PSE voltage - Verify VOITA converter output at J1 terminal block:

   • Should read 48V nominal (47-49V acceptable)
   • If below 47V, converter may be faulty or underpowered
   • Measure under load (with devices connected)

2. Measure voltage at device end - Use a PoE tester to verify voltage at the end of the cable:

   • PoE testers (also called PoE meters or PoE detectors) plug directly into the RJ-45 port
   • They display voltage, current, power, and PoE class
   • Connect the tester to the end of your 100ft cable (where the camera would plug in)
   • Expected readings:
     • Voltage should be ≥37V (IEEE 802.3at minimum at PD)
     • If voltage is below 37V, voltage drop is the problem
     • Compare to voltage at PSE (J1 terminal) to calculate actual drop
   • Affordable PoE testers with voltage display:
     • YGiTK Line Location Finder POE (~$38 on Amazon) - Measures PoE voltage up to 60V, shows voltage, polarity, and PSE type (af/at) on LCD screen
     • VXSCAN NF-488 (~$40) - Shows voltage, current, power on LCD display
     • NOYAFA NF-488 (~$40) - Similar inline tester with voltage readout
     • OONO F-1075 (~$17) - LED-based detector (shows PoE presence but not exact voltage)
   • Professional options: Klein Tools VDV526-052, Fluke Networks LinkRunner (more expensive)
   • Alternative: PoE splitter with voltage display can also show voltage at device end

3. Reduce power per port - Set ports to AF mode (15W max) to reduce current:

   # Set port to AF mode (15W instead of 30W)
   echo "set-af-mode 0 <port>" > /proc/pse
   

   Lower current = less voltage drop over cable

4. Use higher quality cables:

   • Cat6 or Cat6a has lower resistance than Cat5e
   • Better quality = less voltage drop
   • Ensure all 8 wires are properly terminated
   • Avoid damaged or kinked cables

5. Check individual device power requirements:

   • Some cameras draw more power than others
   • PTZ cameras may need full 30W
   • Basic cameras typically need 5-8W
   • Try the problematic camera on a short cable first to verify it works

6. Verify cable quality:

   • Test with a known-good cable of same length
   • Check for damage, kinks, or poor terminations
   • Ensure cable is Cat5e or better (not Cat5)

7. Consider cable length limits:

   • IEEE 802.3 spec: 100m (328ft) maximum for Ethernet (applies to PoE)
   • Verified: We have tested and verified operation at 300ft (91m) with Cat6 cable
   • Practical limit: Depends on cable quality, device power draw, and PSE voltage
   • If consistently failing at long cable runs, check PSE voltage, cable quality, and power mode

Intermittent power delivery

Symptoms: Device powers on then off randomly.

Solutions:

1. Check total power budget:

   head -20 /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 completely
   • Unlock clips on both connectors
   • Remove cable
   • Inspect for damage
   • Reinsert and lock

2. Check cable orientation:

   • Contacts face up (printing visible on top)
   • Blue reinforcement tape faces down

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

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 (press Ctrl+C to stop)
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
head -30 /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 support@exaviz.com with:
   • Diagnostic output
   • Description of the issue
   • Steps you’ve already tried

Last modified February 25, 2026