Some car devices such as some speed radar dectors use RJ11 for power cord. E.g. the Uniddn R4 speed radar detector. What is the upside of using RJ11? I would have guessed that se UBS types would've been more commonplace than RJ11.

1 Answer 1


The RJ11 was invented in the 1960s. Over the next 20 years, it became widely available, dirt cheap and highly reliable as used in telephony, with an installed base likely in the billions.

Cincinnati Microwave, today known as Escort, began using the RJ11 on their radar detectors in the 1980s. It checked all the boxes for cost, user friendliness, reliability and number of conductors. I can't prove that Escort was the first to use the RJ11 but every radar detector that I was aware of before that, including the Fuzzbuster and the Whistler, was using a hard wired cable. Other radar detector manufacturers certainly recognized a good choice in connectors and likely copied Escort.

USB was invented in 1996. Since the RJ11 still fulfilled all requirements, there was no reason for Escort or anyone to change their designs to USB, and some incentive to retain the old design for backwards compatibility with existing detectors.

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