SONOFF BASICR2 Vs BASICR3: DIY Mode and More Features

You’ve maybe noticed that we have rolled out the new version SONOFF BASICR3 smart switch a while back. And you think about: BASICR2 is the best. No, BASICR3 is also the best. Well, which is it on earth? No doubt almost all of us believe that there are more innovations and features in the new version so that it can catch more attention than the old one. Of course, BASICR3 is no exception. However, you must be curious about what the difference is BASICR3 and BASICR2. Before going any further, what you need to know is – both BASICR3 and BASICR2 are smart switches, and they can get the tasks done perfectly to make homeowners ease into a smart home. Now let’s bring out the differences!

Appearance & Material

Look at the outside of BASICR3 and more subtly you will find that its specifications are printed on the bottom, and “SONOFF” logo is on the top. The uniformly white color body makes it look simple and exquisite. Compared with BASICR2 finished with silk-screen craftsmanship, BASICR3 takes the form of engraving which ensures specifications don’t fade away and you will always view them clearly albeit it’s used for a long time. Another improvement is its material. BASICR3 is made of PC (V0 rating), which features high heat-resistance, flame-retardance, impact-resistance and heat aging resistance, ensuring your appliances are safer in use. BASICR2, however, adopts ABS (V0 rating) material that is inferior to BASICR3 in the aspect of heat aging resistance. BASICR3 comes with wire fasteners to ensure the extremely firm installation between wires and the unit but, BASICR2 does not.

Unique Feature – DIY mode

As you might expect, which feature is added to the new version BASICR3? It supports the DIY mode (designed for developers) which allows developer users to integrate BASICR3 into worldwide third-party open source smart home control system to achieve LAN control without cloud service, such as Home Assistant, openHAB, ioBroker, etc. In DIY mode, the BASICR3 publishes its capability service followed the mDNS/DNS-SD standard discovery protocol [1]. How to discover the BASICR3? The discovery process searches in the LAN with default SSID and password [2] for all devices with the service type _ewelink._tcp through the DNS PTR record, parses out the corresponding “Device ID” through the DNS TXT Record, and then gets the device configuration and status information according to “Device Information” in DNS TXT Record. With such global search, The BASICR3 typed _ewelink._tcp is discovered in your developed application, you also can figure it out from our demo tool and source code [3]. The BASICR3 opens the HTTP server in the port declared by the DNS SRV record and publishes the services and capabilities through a HTTP-based RESTful API, the RESTful API Request works in POST method and JSON formatted request body while Response works in 200 OK HTTP response code. Users are able to control the most key functions of BASICR3 in DIY Mode via LAN with their own application or existing smart home control system.

RESTful API control functions

RF Performance

The RF performance is the key transmit & receive capability of the device, Have you ever met the issues of “device can not be found”, “pairing for a long time”, “Not able to pair as the Wi-Fi signal is acceptable”, “control operation delay?” The BASICR3 overcomes such cases by improving RF performance. We will present you the RF performance data tested in SONOFF laboratory with the comparison of BASICR3, BASICR2 and another similar product from European famous brand (here we call it “A” product) in terms of average power, peak power, EVM (Error Vector Magnitude), CFO (Carrier Frequency Offset) and receiver sensitivity. We choose 3 channels respectively to test in high, medium and low frequency out of totally 14 channels of wireless 2.4GHz. Here is our test result.

1) Average & Transmission Power

The transmission power is the amount of power (in dBm) of radio frequency energy that a transmitter produces at its output. As the signal of the transmitter pass through the attenuation of the space before it can reach the receiver, in the condition of acceptable transmit spectrum mask and EVM index, the greater the transmission power, the better linearity and larger wireless coverage is. We evaluate the transmission power performance by Average Power and Peak Power. From below data, the BASICR3 transmission power is the best one compared with BASICR2 and “A” product.

2) Error Vector Magnitude (EVM)

EVM is a measurement index used to quantify the performance of a digital radio transmitter or receiver. Because of the imperfections of the signal such as carrier leakage, low image rejection ratio, phase noise etc., the actual constellation points will be deviated from the ideal and the constellation deviation was named as an error vector in the I-Q plane. EVM is the average amplitude of the error vector, normalized to peak signal amplitude.

From the below data, the EVM value of BASICR3 is about -30dB in certain test frequency which is lower than BASICR2 and “A” product, namely the minimum deviation of constellation points occurs on BASICR3, in another words, the BASICR3 transmission signal quality is the best and the device is able to quickly respond to your every operation.

3) Channel Frequency Offset (CFO)

The channel frequency offset is a deviation index of frequency from the center standard channel frequency. There are two factors of the channel frequency offset cause, the frequency doesn’t match in the transmitter and the receiver oscillators, and the Doppler effect while the transmitter or the receiver is moving. In BASICR3 application scenario, the mismatch of frequency between transmitter (BASICR3) and Receiver (Wi-Fi router) is dominated. As the standard Wi-Fi 2.4GHz channel carrier frequency is definite, we select channel 1/6/11 to test the channel frequency offset of DUTs. With a smaller channel frequency offset value, the transmission signal frequency of DUT is closer to the center channel frequency. From our test data, both BASICR3 and BASICR2 channel frequency offset values are within 10 ppm which is far less than IEEE 802.11 WLAN the oscillator precision tolerance±20 ppm, and also better than “A” product.

4) Receiver Sensitivity

Receiver sensitivity is defined as the minimum signal power level with an acceptable Bit Error Rate (in dBm) that is necessary for the receiver to accurately decode a given signal. A receiver with a smaller (more negative) sensitivity rating will be able to detect weaker RF signals and demodulate the data in a wider wireless coverage. Through testing, we noticed the receiver sensitivity value of BASICR3 is the best, up to -72.3dBm around. This indicates the capability of receiving data of BASICR3 is better than BASICR2 and “A” product.


The BASICR3 achieves the CE (Directive 2014/53/EU) and FCC compliance [4] for the conformity with health, safety, and environmental protection. The product certification testing was done by an authoritative certification organization named Bay Area Compliance Laboratories, Corp. (Notified Body number: 1313) [5] which is located in United State, specializing in international certification and testing for wireless communication products and accredited by NIST (National Institute of Standards and Technology).

Below are part of the certification body that BACL obtains:
FCC TCB authorized by A2LA (USA)
SCC authorized by Canada, IC certificate is available
CAB authorized by EU
MIC CB authorized by Japan

This article lays out the differences of BASICR3, BASICR2 and “A” product for the material, feature, performance and certification as to which one is better in home automation. Well, let me restate that BASICR3 is safe and durable in material, user-defined in function, wider in transmission range, quicker in response operation, faster and more accurate in data receiving, guaranteed in quality. Most importantly, BASICR3 is certified by the authoritative company that ensures a great performance and quality verification. All of the above characteristics are unparalleled for BASICR2 and “A” product. Now, SONOFF BASICR3 is ready to lift your experience to the next level, are you ready to access?


[1] Multicast DNS protocol: IETF RFC 6762,
     DNS‑Based Service Discovery protocol: IETF RFC 6763,
     Zero Configuration Networking: Zeroconf,
     Apple Bonjour Network Discovery and Connectivity: 
[2] Default SSID: sonoffDiy
     Default Password: 20170618sn
[4] CE and FCC certifications and test reports:
[5] Bay Area Compliance Laboratories, Corp notified body number.:

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