n055

blueprint:
  name: IKEA E2490 BILRESA Scroll Wheel (Zigbee2MQTT + ZHA)
  description: |
    Unified controller blueprint for IKEA E2490 BILRESA scroll wheel working with Zigbee2MQTT and ZHA.
    - Buttons: on, off, on_double, off_double
    - Scroll: brightness_move_to_level with action_level from Zigbee2MQTT main topic, or ZHA move_to_level args
    Supports light brightness, media_player volume, light color_temp, light hue.
    Version: 2026-01-18
  domain: automation

n055

Connecting a VT420 to a Linux PC

Hardware

The DEC VT420 terminal only has 6P6C MMJ connectors. We need a converter to make this work with a standard serial to USB adapter. The originals are hard to find or expensive, but we can assemble one new.

• D9 Female to DEC MMJ. You need to wire up the DE-9/DB9 plug's wires to the adapter's MMJ jack yourself. They actually sent me a DE-9 male adapter by mistake, so I ended up just using an easily obtainable DE-9 gender changer once I'd wired up the adapter.

• MMJ Null Modem Cable. You could also use a cable that isn't a null modem cable, and use a null modem adapter/cable on the DE-9 side. Or, you could wire up the D9 to MMJ adapter to be null modem.