---
title: "Serial ports"
canonical: "https://docs.cuesystem.com/space/PRODUCTS/292159597/Serial%20ports"
format: markdown
---
## Overview

This type of port provides a connection to controlled devices through RS-232/422/485.

The following types of serial ports are available:

> Macro (children)

The following table provides an overview of controllers and serial ports.

|  |  |
| --- | --- |
| Unit | Serial port |
|  | RS-232/485 | RS-232/422/485 | RS-232/422/485 with power 24 VDC |
| controlVUE-basic | 1 |  |  |
| controlCUE-versatile | 3 |  |  |
| controlCUE-one |  | 1 | 1 |
| controlCUE-two |  | 5 | 1 |
| controlCUE-three | 4 |  |  |
| controlCUE-versatile-d | 3 |  |  |
| controlCUE-dali-d | 1 |  |  |
| controlCUE-knx-d | 1 |  |  |
| controlCUE-dmx-d | 1 |  |  |
| controlCUE-enocean-d | 1 |  |  |
| smartCUE-versatile | 3 |  |  |
| smartCUE-versatile-d | 3 |  |  |
| smartCUE-relay | 3 |  |  |

The basic parameters for the most commonly used serial ports are listed in the following table.

|  |  |  |  |
| --- | --- | --- | --- |
| Parameter | RS-232 | RS-485 | RS-422 |
| Mode of operation | Single ended | Differential | Differential |
| Drivers per line | 1 | 32 | 1 |
| Receivers per line | 1 | 32 | 10 |
| Maximum cable length | 15 m | 1 200 m | 1 200 m |
| Driver output maximum voltage | ±25 V | -7 to +12 V | -0.25 to +6 V |
| Driver output signal level (loaded) | ±5 V | ±1.5 V | ±2 V |
| Driver output signal level (unloaded) | ±15 V | ±5 V | ±5 V |
| Driver load impedance | 3 kΩ to 7 kΩ | 54 kΩ | 100 kΩ |
| Max. driver output current (Power on) | n/a | ±100 mA | n/a |
| Max. driver output current (Power off) | V<sub>MAX</sub> / 300 Ω | ±100 mA | ±100 mA |
| Receiver input voltage range | ±15 V | -7 V to +12 V | -7 V to +7 V |
| Receiver input sensitivity | ±3 V | ±200 mV | ±200 mV |
| Receiver input resistance | 3 kΩ to 7 kΩ | 12 kΩ | 4 kΩ |