This is an update. After seeing several good reviews from recent 2023, all mentioned 'pairing' . I looked more closely at the INSTRUCTION paper included with the new receiver I had ordered because i thought the new add-on transmitters i had ordered didn't work with the old receivers we had. With a magnifying glass it had the pairing instructions. When i followed that procedure - ALL the add-ons i was going to return , thinking i had to buy from a different manufacturer , WORKED BEAUTIFULLY !!!!!! The Day Was Saved by your informative reviews !!!!!!!

I already had the doorbell system that this pairs with, but the old doorbell piece had to be removed during a door replacement. I was going to reinstall it, but it had yellowed over time and the signal was a bit erratic, occasionally sounding the doorbell chime when no one was there. (It was a few years old.)

After some research, it seemed I could pair this remote doorbell piece with my existing bases, and I'm happy to report that it worked! The entire system is super simple to install - just plug in the base(s), choose a doorbell chime, attach the doorbell to your desired location, and voila! Instant doorbell without wiring! Love it!

I'm very pleased that this system allowed me to replace only the doorbell piece without having to re-purchase the bases, making it more sustainable. I highly recommend this system and replacement doorbell part.

My 4 year old transmitter started just ringing in the middle of the night when there was no one at the door. Ruled out ghosts and determined it was because rain water was shorting it out. Ordered this one that was waterproof and it was DOA. I switched the battery out of my 4 year old unit and paired it up and it works great. I ordered new batteries and will swap out a new fresh battery when it arrives. After the old transmitter is dry I will install it on my back covered deck.

So, if your transmitter is dead on arrival it is probably just a bad battery.

So I originally bought this Sadotech wireless doorbell system in 2015. It is still working to this day, but after 8 years of Wisconsin weather, the buttons outside no longer looked new. I cleaned them a few times, and changed the batteries, when needed, but it was time to replace them. So I ordered two new buttons (transmitters). The new transmitters looked nice, but I could not get the old receiver to go into the pairing mode. So then I bought a new plugin receiver, which easily went into the pairing mode, like it should, So now I have two new transmitter buttons, and a new plugin receiver, and everything looks nice, and works great. They still make a good wireless doorbell system, that's easy to install, at an affordable price.

This is an updated review. The original product that I received was defective. The rating (4 stars) is based on excellent customer service, but lackluster quality assurance. Beware if you are in a rush to get your new doorbell system up and running, as you might need to return some defective components. But the seller has a history of being reasonable about such returns.

In my case, after jumping through the hoops of returning the defective unit using the Amazon return process, the seller contacted me and sent me (without me requesting it) two functional replacement door sensors: one that is the same model I ordered, and another new-and-improved model. Both replacements worked without a hitch.

Regarding the older model, described below, the seller provided an explanation for the mysterious 2nd LED indicator: it is used to indicate a low-battery condition. Apparently it illuminates, or blinks, when the unit's battery level falls below a certain threshold. If the bottom LED does not illuminate then either 1) the battery has adequate power, or 2) the battery is completely dead or missing. The new model of door sensor lacks the 2nd LED, and that's just as well. The new model also lacks an external antenna (it has an internal antenna instead), and includes a page of instructions specific to the door sensor: both welcome improvements.

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Original review:

I ordered this item along with the Base Starter Kit (includes 2 Plugin Receivers and 2 Remote Button Transmitters) sold by the same company. The video [...] provided for pairing STARPOINT compatible receivers, buttons, and this sensor, were adequate. But the video provided no information specific to this particular door sensor. So, even though the linking process was apparent from the video, the unique properties of the door sensor (e.g., proper installation, the purpose of the two LEDs, etc.) were not explained.

The Model LD is remarkably small: 7 cm x 3.5 cm x 1.7 cm. The accompanying magnet is 6.4 cm x 1.2 cm x 1.7 cm. The telescoping antenna on the sensor box extends to about 10 cm from the top of the sensor chassis box.

Linking the doorbell button transmitters to the plugin receivers worked without a hitch. Linking the Model LD door sensor was difficult, requiring multiple tries. Once linked, it rarely triggered the audible tone in the receivers even from very short range. Moving the magnet away from the sensor resulted in one of the LEDs illuminating consistently each time the "door open" condition was simulated, but it only triggered an audible tone in one of the receivers occasionally - perhaps once in 20 attempts.

Upon contacting Sado tech support by email I received a prompt reply. After an exchange of 8 emails, and several repeated attempts to make the sensor work, the support person was finally convinced that the sensor was defective. I was instructed to return the Model LD sensor using Amazon's return process: which I have now done, and am waiting for the replacement to arrive. I will update this review when the replacement arrives and has been tested.

The Model LD comes with no instructions. Though it isn't terribly complicated to pair and use, there are puzzling aspects to this device. It features a telescoping antenna: should it always be deployed, or only deployed if additional range is needed? Is vertical or horizontal preferred? The Model LD features two LED indicators: one illuminates briefly when the door is opened, but what does the other one indicate? (The second LED on my defective unit never illuminated.) How should the sensor and magnet be mounted to the door: Does it matter which side of the sensor the magnet is on: the left, the right, the top, or the bottom of the sensor? (In my experiments with a defective unit, the magnet needed to be on the righthand side of the sensor when viewing the sensor from its front - which could impact how the unit can be properly installed on various door styles and opening directions.

Attached is a picture of my defective Model LD with its single LED illuminated - indicating that the magnet has just moved out of range. Even customer support could not explain the purpose of the second LED. In the photo the magnet is shown on the only "correct" side on which it needs to be mounted relative to the sensor.