FAQ

General Questions

How many PoE ports can I have?

• Single board: 8 ports
• Dual boards: 16 ports (maximum supported by the Interceptor Carrier Board)

Each PoE board provides 8 ports. The carrier board has two FFC connectors (J9 and J10) for connecting up to two PoE boards.

What PoE standard is supported?

The Interceptor PoE Board supports IEEE 802.3at (PoE+), which provides up to 30W per port. It is also backward compatible with IEEE 802.3af (PoE) devices.

Can I use the PoE ports for regular Ethernet?

Yes, the PoE ports function as standard 10/100 Mbps Ethernet ports even when PoE is disabled. However, for Gigabit speeds, use the carrier board’s 4-port switch (J8).

What speed are the PoE ports?

The PoE ports operate at 10/100 Mbps (Fast Ethernet). This is sufficient for most PoE devices like IP cameras, WiFi access points, and VoIP phones.

For Gigabit connectivity, use the carrier board’s built-in 4-port Gigabit switch.

Power Questions

What power supply do I need for PoE?

The PoE boards require:

1. VOITA 48Vdc Power Converter - Converts PSU 12V to 48V
2. ATX PSU with adequate 12V rail capacity

PSU Recommendations:

How much power does each device typically use?

What happens if I exceed the power budget?

If total power demand exceeds supply capacity:

• Individual ports may reset or enter fault state
• System voltage may become unstable
• Connected devices may power-cycle randomly

Always calculate your power budget before deployment.

Control Questions

How do I enable/disable PoE on a specific port?

Use the /proc/pse interface:

# Enable port 0 on board 0
echo "enable-port 0 0" > /proc/pse

# Disable port 0 on board 0
echo "disable-port 0 0" > /proc/pse

# Check status
cat /proc/pse

Why doesn’t ip link set control PoE power?

The ip link set command controls the network interface, not the PoE power delivery. These are separate functions.

ip link set poe0 down    # Only disables network, NOT PoE power
echo "disable-port 0 0" > /proc/pse  # Actually disables PoE power

Can I control ports without root access?

No, writing to /proc/pse requires root privileges. You can:

1. Use sudo:

   echo "enable-port 0 0" | sudo tee /proc/pse
   

2. Create a privileged script or service

3. Set up sudo rules for specific commands

Can I set ports to enable automatically on boot?

Yes, create a startup script:

1. Create /usr/local/bin/poe-init.sh:

   #!/bin/bash
   for port in 0 1 2 3 4 5 6 7; do
     echo "enable-port 0 $port" > /proc/pse
   done
   

2. Make it executable:

   chmod +x /usr/local/bin/poe-init.sh
   

3. Add to your init system (rc.local or systemd service)

Installation Questions

Which way does the FFC cable go?

• Blue reinforcement tape faces UP (toward the locking clips)
• Contacts face DOWN (toward the PCB)
• Cable should be fully inserted before locking clips

Can I hot-plug the FFC cable?

No. Always power off the system before connecting or disconnecting FFC cables. Hot-plugging can damage the board or corrupt data.

Do I need both PoE boards connected?

No, you can use just one PoE board connected to J9. The second connector (J10) is optional for expansion to 16 ports.

Compatibility Questions

Will any PoE device work?

Most PoE devices work, but verify:

1. Device supports 802.3af or 802.3at
2. Device power requirement is under 30W
3. Device works with 100 Mbps Ethernet (not Gigabit-only)

Can I power a Raspberry Pi via PoE?

Not directly from the Interceptor PoE Board. The Pi uses a non-standard PoE HAT. However, you can use a PoE splitter that provides 5V Micro USB output.

Can I use passive PoE devices?

Not recommended. The Interceptor PoE Board uses standard IEEE 802.3at PoE, which requires proper negotiation. Passive (non-standard) PoE devices may not work or could be damaged.

Troubleshooting Questions

My device won’t power on from PoE

1. Verify device is 802.3af/at compatible (not passive PoE)
2. Check port status: cat /proc/pse
3. Enable the port: echo "enable-port 0 X" > /proc/pse
4. Try a different cable (Cat5e or better, all 8 wires)
5. Try a different port

The /proc/pse file doesn’t exist

• Update to exaviz OS 2025-05-01 or newer
• Check FFC cable is connected
• Check 48V power is connected
• Verify driver is loaded: dmesg | grep ip808

Port shows “fault” status

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

More Questions?

Contact info@exaviz.com with your question.

Last modified December 30, 2025