TP-BUS interface and KNXD daemon

This article explains how to install the knxd daemon on a CM3-Home and use it with the TP-BUS interface.

Tested with a standard Raspbian Stretch Lite - November 2017

Please note:
The CM3-Home board IS NOT a certified KNX device but implements just a hardware circuitry based on a Siemens TP-UART-2. Acme Systems doesn't provide any warranty about its functionality with the KNX devices.

The TP-UART-2 circuitry is powered up by the external bus so in order to guarantee the correct operation provide the power supply to the bus before turning on the CM3-Home.

In this article we will control a KNX relay PLANA 1453 made by Vimar wired as shown below. The relay address was already configured.

Compiling KNXD from sources

Install the following packages:

sudo apt-get install git-core build-essential
sudo apt-get install debhelper libsystemd-dev dh-systemd libev-dev

Clone the knxd repository on GitHub:

git clone

Build knxd:

cd knxd
dpkg-buildpackage -b -uc

Install the package:

cd ..
sudo dpkg -i knxd_*.deb knxd-tools_*.deb


The default installation will install two services:

  • knxd.service
  • knxd.socket

In this example we will not use knxd.socket so disable it by typing:

sudo systemctl disable knxd.socket

Remove the actual contents of /lib/systemd/system/knxd.service with this contents:

Description=KNX Daemon

ExecStart=/usr/bin/knxd $KNXD_OPTIONS



Remove the actual contents of /etc/default/knxd with this contents:

KNXD_OPTIONS="--eibaddr=1.1.128 --client-addrs=1.1.129:1 -D -T -R -S -i --listen-local=/tmp/knx -b tpuarts:/dev/ttyAMA0"

Reload systemd in order to detect the new service definitions:

sudo systemctl daemon-reload

Let's try to control the KNX relay

Open and SSH session and launch the follow command to check what is the messages sent:

knxtool busmonitor1 ip:localhost

Open a second SSH session and type:

Relay ON:

knxtool on ip:localhost 1/6/105

Relay OFF:

knxtool off ip:localhost 1/6/105



EUR 290.00

CM3-HOME-F - CM3-Home board full (mother board only)

CM3-Home is a Raspberry Pi Compute Module 3 motherboard designed to provide a reliable Home Automation hardware equipped with a wide range of electrical interfaces

    • Raspberry Compute Module 3 or 3L (Product # CM3L)
    • Yarm antenna (Product # YARM-ANT-01)
    • Case (Product # CM3-HOME-CASE)
    • MicroSD (Product # MICROSD8G-E)
  • Included:
    • WiFi module (Product # WIFI-2)
    • WiFi antenna (Product # AN-WIFI-01)

For more info please visit the product description page

| Product description || CM3-Home catalog |

Sergio Tanzilli
System designer, software developer and company co-founder
Webpages: and
Github repository: and
Guido Ottaviani
Hardware designer, firmware developer, technical writer and robotics specialist
Github repository: