====== Ericsson / Alpha-American 4200C LED Sign ======

This page documents the large LED sign acquired by Hackeriet, gifted by pere and asle.{{ :infra:led-sign1.png?600 |}}

===== Overview =====
This is an **Ericsson-branded, Alpha-American / Adaptive Micro Systems 4200C LED sign**.

It is a programmable LED display commonly used for transit, public information, or industrial messaging systems.

  * **Model:** 4200C
  * **Manufacture Date:** 2004-04-08
  * **Power:** 100–240V AC, 50/60Hz, 1.5A
  * **Status:** Fully operational, displaying test message on boot. Unknown operational method.
  * **For indoor use only.**

===== Ports =====
{{:infra:led-sign2.png?100 |}}The sign has a **RJ-style modular port** on the back panel with:
  * RS-232 IN
  * RS-485 IN
  * RS-485 OUT


It also has an IR sensor hidden behind a red sticker, visible when removing a panel.

===== Dongle =====
{{:infra:led-sign3.png?100 |}}A small dongle with resistors was included, likely serving as a **RS-485 termination and bias dongle**.

===== Communication =====
The sign probably uses the **Alpha Sign Communications Protocol**, which is:
  * A structured serial protocol using STX/ETX framed packets.
  * Allows sending:
    * Text messages
    * Control commands (clear, brightness, modes)
    * Time-based messages

===== Serial Configuration =====
Suggestion for initial connection (untested):
  * **Interface:** RS-232 IN (single device)
  * **Baud rate:** 9600 or 19200
  * **Data bits:** 8
  * **Parity:** None
  * **Stop bits:** 1
  * **Flow control:** None

===== Resources =====
  * [[https://www.alpha-american.com/Technical-Manuals.html|Alpha American Technical Manuals]]
  * [[https://www.alpha-american.com/alpha-manuals/M-Protocol.pdf| Alpha® Sign Communications Protocol]]