# General information

<table border="1" id="bkmrk-download-technical-s" style="border-collapse: collapse; width: 100%;"><colgroup><col style="width: 50%;"></col><col style="width: 50%;"></col></colgroup><tbody><tr><td>Download technical specification</td><td>[Technical Specification](https://www.atreyo.in/sites/default/files/a-download/AMB-4I-4O%20Technical%20Specification.pdf)</td></tr></tbody></table>

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#### Wiring

The expander has opto-isolated inputs that require an external power supply. This requires a 5-30V power supply. The inputs can be driven by both positive and negative signals. Both examples are shown in the attached diagram.

The outputs of the expander are directly connected to the relay leads. The relays are of normal open type.

![AMB-4I-4O wiring.png](https://docs.atreyo.in/uploads/images/gallery/2025-02/scaled-1680-/amb-4i-4o-wiring.png)