Both Phoscon and Zigbee2MQTT are programs for controlling a Zigbee gateway, like the Conbee 2. The primary task of a Zigbee gateway is to connect and centrally control Zigbee devices. After initial difficulties with stability, Phoscon worked relatively well for me recently, but after more than a year of deCONZ and Phoscon I switched to Zigbee2MQTT.One reason for the change was a dimmer switch, which I did not get stable under Phoscon until last: Sometimes it worked, sometimes not, see also: Conbee 2: Phoscon deCONZ - Unstable - Connection lost. I have read about Zigbee2MQTT as an alternative, but so far I wanted to save the effort of having to re-learn all devices. After a quick test with one lamp in Zigbee2MQTT, all lamps remained offline after the test and when restarting Phoscon. From that point on I had nothing to lose and turned my back on Phoscon .

Similarities

The main focus of a Zigbee gateway is to communicate with its connected Zigbee devices, for which both solutions are suitable. I was able to integrate a wide variety of deviceswith both Phoscon and Zigbee2MQTT, so far for me also no decision criterion for one of the solutions. Both gatewaysdo not offerthe possibility to create their own dashboards or to record or display historical data, but the two can be easily integrated into another smart home solution such as ioBroker or Home Assistant.

Phoscon and deCONZ

The web interface Phoscon distinguishes between lights, sensors and switches, accordingly starts the connecting of the devices in one of the three categories. At first glance, the Phoscon interface seems modern and makes it easy to connect the devices, as well as to divide them into groups or to set actions for these groups. As an example, several lamps can be combined into a group, certain scenes can be bound to them and these can be mapped to any buttons of a dimmer switch. Not all parts of the web interface can be managed via a mobile device: Certain functions are reserved for a PC, as they are not supported for mobiles. Some elements work via the detour on the smartphone after the display has been changed to "desktop website", but sometimes there is simply a message that the action is not possible on mobiles. Not enough, there are also advanced options that are then only possible via a VNC connection, on an interface that could be from the last millennium. As an example, firmware updates (OTA) or the direct connection of switches to certain devices (binding) can only be done via the VNC interface.

Compatibility: phoscon.de/en/conbee2/compatible

Advantage

• Creation of scenes,
• certain scheduled tasks, like switching on certain devices or activating scenes at a time
• certain actions after triggering a sensor. e.g. switching on a light when a motion sensor is triggered
• arbitrary mapping of single buttons of a switch

Disadvantage

• Two different management interfaces: the Phoscon web interface and deCONZ (via VNC).
  • Missing binding in the web interface Phoscon
  • Missing possibility of OTA updates in the Phoscon web interface
  • Cumbersome and unclear administration interface via VNC on deCONZ
• Certain actions, such as creating scenes, do not work from a mobile device.

Zigbee2MQTT

The name Zigbee2MQTT is program: Zigbee2MQTT concentrates purely on functions concerning Zigbee: Connecting, reading and controlling devices, firmware updates, groups and bindings. For further use of the sensor data or for controlling the devices a MQTT broker is required. Zigbee2MQTT alone can display sensor data, control devices and bind them, but only makes sense with MQTT and another SmartHome solution.

Advantage

• simple and clear management interface
• Clear separation of tasks: The task of Zigbee2MQTT is to address the Zigbee devices and provide their functions and data via MQTT.
• high number of supported devices: current number of supported devices: 3900 von 451 Manufacturers, see: www.zigbee2mqtt.io/supported-devices/
• Possibility to connect and integrate non-supported devices anyway, see commissioning Zigbee2MQTT

Disadvantage

• Zigbee2MQTT only makes sense by using an MQTT broker and additional software like Home-Assistant , because:
  • Zigbee2MQTT alone can not perform automation tasks
  • Zigbee2MQTT alone can map certain buttons of a switch
• Due to the need of an additional MQTT broker, the setup is more complex at the beginning, see Home-Assistant Docker Conbee 2 and Zigbee2MQTT / deCONZ

ZHA

Those who use HomeAssistant can use ZHA as a third variant for their Zigbee devices. See also: ZHA commissioning and change of Zigbee2MQTT

Conclusion

Phoscon is certainly not bad, even the interface seems very intuitive and modern at first. One of the advantages is that within the web interface some scenarios, like automatically switching on a light at a certain time or mapping certain scenes to a button of a switch are easily implemented, nevertheless Phoscon quickly reaches its limits away from predefined functions. If you want more than the predefined functions, you will quickly end up with an additional SmartHome solution like ioBroker or HomeAssistant. Compared to Phoscon, Zigbee2MQTT can do much less out of the box, but if you use an additional SmartHome solution anyway, you get a much more consistent installation with Zigbee2MQTT and the additional SmartHome solution. The tasks are thus clearly distributed: Zigbee2MQTT is purely responsible for connecting and managing the Zigbee devices - which it masters perfectly, additional tasks, like displaying the individual devices in dashboards or certain automation or monitoring functions are taken over by a system that has its focus in the SmartHome area and could also manage other devices apart from Zigbee. Perhaps the comparison Phoscon and deCONZ vs. Zigbee2MQTT could also be summarized like this: In a pure comparison of possibilities, the advantages would clearly lie with Phoscon and deCONZ, in combination with another SmartHome solution, like Home-Assistant, I think Zigbee2MQTT has the edge thanks to the more consistent interface.  Pure for Home Assistant also provides ZHA also offers direct integration into Home Assistant.