Why Somfy Uses 433.42 MHz (Not 433.92 MHz)
One of the most common mistakes when sourcing replacement remotes for Somfy motors is using 433.92 MHz units instead of 433.42 MHz. The two frequencies are close but not interchangeable. This 2026 guide explains the difference.
1. The Frequency Gap
433.42 MHz and 433.92 MHz are 500 kHz apart. Receiver filters cannot pass 433.92 MHz signals to a 433.42 MHz receiver, and vice versa. The radios appear physically similar but are tuned to different bands.
2. Why Somfy Chose 433.42 MHz
Somfy’s RTS protocol uses 433.42 MHz to avoid interference with the more common 433.92 MHz ISM band used by other home automation devices. This deliberate choice reduces false triggering in mixed installations.
3. How to Identify the Correct Frequency
Look at the back of the original remote. Somfy remotes have a label showing “433.42 MHz” or “RTS”. Replacement remotes must match. Generic 433.92 MHz clones will not pair with Somfy receivers.
4. Sourcing Correct Replacements
For distributors, this means stocking 433.42 MHz Somfy-compatible remotes separately from 433.92 MHz generic units. The housings may look identical, but the firmware and radio module differ.
5. Field Verification
If a customer reports pairing failure with a Somfy-compatible remote, the first check is the frequency. A wrong-frequency remote will pair with some Chinese universal clones but fail with authentic Somfy receivers.