Troubleshooting: No Signal Between Encoder and Decoder

Troubleshooting: No Signal Between Encoder and Decoder

Overview

If a KanexPro AV over IP decoder shows no signal, a black screen, or frozen image, work through the steps below in order. Most issues are caused by network misconfiguration, IGMP settings, or IP addressing conflicts.

Step 1 — Verify Physical Connections

  • Encoder HDMI input connected to an active source outputting video.
  • Decoder HDMI output connected to a powered display set to the correct input.
  • Both devices connected to the same managed switch via Ethernet.
  • All Ethernet cables are CAT5e or better; link LEDs lit on both device and switch port.

Step 2 — Verify Network Switch Settings

  • IGMP snooping: Must be enabled globally and on the AV VLAN. This is the #1 cause of no signal on first install.
  • IGMP querier: Must be enabled on the AV VLAN if no multicast router is present.
  • Jumbo frames: JPEG2000 and SDVoE require MTU 9000. Mismatch causes packet fragmentation.
  • Flow control: Must be disabled on all AV ports.
  • Port speed: JPEG2000/H.265 require 1G; SDVoE requires 10G.

Step 3 — Verify IP Addressing

  • Encoder and decoder must be on the same IP subnet.
  • Check for IP conflicts — duplicate IPs cause intermittent or no signal.
  • Access each device’s web GUI via its IP in a browser. Unreachable = IP conflict or DHCP issue.

Step 4 — Verify Routing Assignment

  • If using an IP controller, confirm the encoder is routed to the correct decoder.
  • An unassigned decoder shows no signal even on a correctly configured network.

Step 5 — Check HDCP

  • HDCP-protected sources require HDCP-capable displays. Test with a non-HDCP source to isolate.

Step 6 — Reboot Sequence

  1. Power off decoder. Power off encoder. Wait 10 seconds.
  2. Power on encoder, wait 30 seconds. Power on decoder, wait 30 seconds.

Step 7 — Factory Reset

Reset both devices using the rear panel reset button, then reconfigure via the web GUI.

Still No Signal?

Contact KanexPro support at support@kanexpro.com or 888.975.1368 with: SKU, switch make/model, IGMP and MTU settings, IP addresses of both devices.

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