Visonic MCT-340 E

I’m brand new to the board and SmartThings so I apologize ahead of time if this is answered. I’m not a developer or have a background in this type of thing.

I purchased a few of the Visonic MCT-340 E door/window sensors. When I try to add a device, nothing is showing up. All I have to do is select add a device, correct? It looks like maybe in the past I needed to be a developer or have some back end knowledge to add these but I see it says they should be native to the app now.

Are there easy step by step instructions to set these up? I appreciate the help!

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They are natively supported and use the SmartSence Open/Closed Sensor.


when you start the pairing process in ST by choosing Add a Device…

  1. Remove the battery cover.
  2. Press and release the tamper switch for 1 to 2 seconds.
  3. Close the battery cover.
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Mine go offline quite a bit. Have to do what jkp said to get them back online.

Hi all! Sorry to bring up and old thread but I’ve got these same door/window sensors and I cannot get them to connect to my ST hub. I’m a brand new ST user (formerly with Iris and then with Wink). Any help would be appreciated. I have like 30 sensors I bought and am
trying to connect.

Try resetting them, then try to pair to ST


I have a bunch of them (Visonic Window/Door Sensor for Samsung SmartThings - MCT-340 E) which I bought back in 2017. They were all working fine with the old app.

I migrated to the new app a few days ago. After a few initial issues with the new app, I did end up deleting and re-pairing them in the new app.

Many things now work OK:

  • The sensors do show up in the list of devices in the new app
  • They work OK in the SmartApps (mostly Smart Lighting) that were migrated over to the new app
  • The SmartThings Home Monitor in the new app does alert correctly when my doors are opened

But there are a couple of things that do not seem to work correctly:

  • In the device list of the new app, the sensor status (open/close) is not shown. In addition, when I tap on those sensors, the new app shows an error: “Can’t connect to the device. Check it and try again.”
  • When I try to create a new Automation in the new app I can’t see any of them listed (Menu > Automations > Plus > If > Plus > Device status)

What experiences have others observed with those sensors after migrating to the new app?


Login to IDE at go to the My Devices section, open each visonic sensor and make sure the device type is set to smartsense open/closed sensor. If they were set to a custom device handler, you may want to remove it from the Device Handler section so it does not cause issues in the future.

I have some visonic sensors and they work fine - they display open/closed and work in automations. :slight_smile:

Note: when building automations, sometimes you need to go into tHe device status section twice in order for all device to load. The first time, not all devices may load, go back, load it again and you will likely get all the devices to load.