---
lang: "en"
title: "KNX SERIAL 870 RS232 interface"
sku: "KNX 870"
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brand: "MARCOM S.r.l."
end_of_life: "false"
---

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KNX SERIAL 870 RS232 interface

KNX Serial 870 is a simple integration solution for non-KNX devices. As an RS-232 interface, KNX Serial 870 uses the proven FT1.2 protocol (PEI 10) as a telegram format. In addition, the device supports the BAOS protocol for data point access. Therefore, the interface is suitable for fully integrating non-KNX devices into a KNX network. A demo tool and an ETS entry with 250 group objects are available for quick start. Of course, individual ETS representations can be created for OEM versions.

For an increasing number of devices, for example in the field of multimedia or security technology, the exchange of control information with building automation is important. For some devices, however, it is advantageous not to access the bus (TP) directly. Instead, a connection to KNX can also be realized via RS-232.

The compilation or interpretation of KNX telegrams, as well as working with group addresses, is left to the KNX/RS-232 interface. In this case, the KNX/RS-232 interface assumes the role of a KNX end device. This means that the device's KNX communication software also manages the data points, so that the device can assign received telegrams to the corresponding communication objects. Likewise, the device can generate and send group telegrams independently. Data point configuration is done with the help of ETS (Engineering Tool Software). In ETS, the interface appears as a conventional bus subscriber. The data types of the communication objects are set via the parameter dialog. Subsequently, group addresses can be assigned as usual.

A client can access data points via RS-232 without having to know the syntax of KNX telegrams. A client addresses a data point via its number. If group addresses are subsequently changed in the KNX network, the interface can be easily updated with an ETS download. It is not necessary to change the client configuration.

The interface supports up to 250 communication objects and has a separate memory location for each of them. Communication object values are automatically updated when received, even if no client is connected. This allows a client to read the process image from the interface without loss of time at startup or wake-up, without loading the KNX bus.

## Technical Specifications

- Housing: plastic
- In-line installation, installation width 1 TE
- Weight: approx. 45 g
- Learning button for KNX
- Learning LED (red)
- Status LED (green) for KNX
- The device is powered by the connected KNX bus
- Current consumption: approx. 10 mA
- KNX connection terminal
- RS-232: SUB-D socket, 9-pin
- Max cable length 5 m

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Source: https://shop.marcomweb.it/en/konnex/knx-serial-870-rs232-interface

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