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There’s no reason Bluetooth stacks couldn’t be open source - unlike a GSM modem, a Bluetooth chipset should only be able to transmit in the 2.5GHz ISM band, whi

There’s no reason Bluetooth stacks couldn’t be open source - unlike a GSM modem, a Bluetooth chipset should only be able to transmit in the 2.5GHz ISM band, which is unlicensed. Even if you can change the LO enough to get outside the band, there should be hardware filtering etc. Of course, commercially available SDRs can transmit in all sorts of bands including licensed ones if you write the code to do so, and there are plenty of open-source applications for SDR, so it’s not like it’s impossible to legally have open firmware for whatever chipsets (even cellular modems)…

kyaghmour 4y ago
It's not just the licensed bands but also SAR. Commercial devices with BT are often close to the body. For those devices to be certified they have to operate within specific power levels, and this has to not be operable/changeable. If you can change power levels, you can bust the SAR limits. It's one thing for geeks to do what they want with SDRs. It's another to get the certification to ship a real product.