I wonder if the Landis and Gyr smart meter E450 is compatible with the Homey dongle? This dongle is suppose to be connected to the P1 port of the type RJ12. However, on the description of the SM E450 I rather see a P2 port?
Here is a picture of the SM E450
Many thank for your help
As an alternative for P1, yo can use the blinking LED, there are devices for that to read-out.
You will probably find a product here::
many thanks for your helpful suggestions. There is one point which is not clear to me yet. Assuming that i use the GplugM dongle, I would like to monitor my energy consummation for one full day. Would I need some additional device like a computer or disk ro store all the data delivered by the Smart meter? Or I am missing some information in the use of the dongle?
your help on this would be greatly appreciated
No idea, you have to ask the manufacturer of the dongle…
Guess the app power by the hour wil be compatible.
@Gervais_Chapuis Did you finally get the gPlugM? How’s your experience?
The L+G e450 has a M-Bus which isn’t compatible to the Homey Energy Dongle. According to my energy provider the gPlugM or whatwatt are compatible (as the manufacturer sites confirm).
There’s a guide on how to connect to Homey that looks manageable…
There’s no similar description to the whatwatt but it has MQTT as well and there’s a HomeAssistant Guide for this.
That was a fast answer by whatwatt:
12 Sep 2025
…
The Homey integration is available as a trial version. The integration was created by Homey itself and we have not yet tested it.That’s right, you need to have a whatwatt Go and a Plus license. All customers who purchase whatwat Go before we activate the licensing (around January 10) will receive the PLUS license free of charge.
As soon as we have tested Homey ourselves, we will make an official announcement.
…
I’ll go with this one as it supports both P1 and M-Bus besides others.
I did not pursue my connection with the Mbus and the g’lug model. This see mes qui te complex for me
I am glad to hear about the new device which could be compatible with Homey. Would be ready to install this device once it has been testés for the Mbus
I can confirm that it works. And installation is ready for normal users.
Whatwatt comes with an app that guides you through the process.
The Homey app is as easy to install.
I had two issues in the first days that could be fixed with a restart of the app.
This is how it look once installed
Many thanks for your message. Indeed this looks very useful. Time to install it. Cheers
I have the gplugm in use (I wrote the above mentioned guide for gplugm and homey) 
If someone has questions - happy to help
The implementation is manual work with virtual devices. But once done it works smooth.
Many thanks for the Information on whatwatt and E450. I was less lucky with my Installation. Did install whatwatt according to the procédure. Once it was set up I did not get any information from my E450. Is it die to the fact that I don‘t have a SIM Card?
Gervais
Hi there’s no need for a SIM card”. The device is using your internet connection via WiFi (or ethernet)
I assume that you need to request “activation” of the interface with your provider.
Thanks for the info concerning the SIM cars. I did receive from the Industrial services of Lausanne (SIL) the permission to access the data of the E450 including the encoding key. Apparently the whatwatt recognize the E450 but complains that no data are receive. Did send a new request to the SIL. Waiting for their answer
Gervais Chapuis
FYI I have not set an encoding key.
