Visonic MCT-320 from xfinity

So I know I have read on forum the MCT-320 does not work, but the MCT-340 does. I don’t have an xfinity MCT-340, but that doesn’t make sense to me. I’m wondering if it’s any door/window sensor from xfinity? According to Visonic there is not much difference in the MCT-320 vs MCT-340 but they made the MCT-340 low profile.

They both pair the same with the xfinity device and show up the same.

I have close to 20 sensors on every door and window in my house, all MCT-320. It’s the only stuff left paired to my xfinity hub for home security. I would love to use them.

I have an extra MCT-320 and I was able to pair it and set it as an MCT-340, but the red light on the MCT-320 just kept blinking. I tried to use the magnet to complete the pair like you do on the xfinity iControl unit, but no luck. It just shows as always open in SmartThings.

I haven’t pulled the source of the MCT-340 yet and done any debugging, but at looking at the system logs when I paired as an MCT-340, I saw nothing come across the logs, so either no good debug outputs in the MCT-340 code or nothing was happening.

Any ideas if this is just a total dead end?

According to Visonic there is a very big difference between the two models as they use different protocols.

There’s no mystery about it. SmartThings uses the zigbee home automation profile (ZHA1.2). Devices that use that protocol can usually be controlled by SmartThings. Devices that do not use that protocol, even if they are using zigbee, usually cannot. Some devices using other zigbee profiles will be able to be paired with SmartThings, but they will not be able to be controlled or they will repeatedly lose connection.

The 340 uses the same protocol as SmartThings.

The 320 is made on a number of different frequencies, but I don’t believe any of them are using ZHA 1.2.

Check the user guide for your particular model and see what frequency and profile it is using.

my information was from a comcast xfinity page, so of course was not reliable…

the thought of replacing all these windows sensors sounds terrible, guess I should start slowly… the terrible thing is I bought about 10-12 more of them not long ago and could have done the MCT-340 and still had it work with my current xfinity alarm if I had been forward thinking, ohh well

now the question to me is invest in slowly replacing the MCT-320 with MCT-340 and until I’m done and my contract is over with xfinity, or is the MCT-340 still a bad device, forget about it, wait until xfinity contract is over, and get some better z-wave door/window sensor at some other point all at once

thanks for the help and specifics, should have looked up info directly from manufacturer

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I think I’m just going to go with the Iris 3320-L, seems like they are cheap and good quality

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Were you able to link the Visonic MCT-340 to Smartthings Hub?
I have the same but am not able to get it to work with Smartthings.

Appreciate your help.


I use several 340s with ST. You may need to go into the Graph and set them up as SmartSense sensors.