5 ms·
To my ear it sounds like AFSK, kind of like the Bell 202 scheme. Here's the first passable search result I found with a clean recording: https://www.youtube.com
by smitelli 1y ago
To my ear it sounds like AFSK, kind of like the Bell 202 scheme. Here's the first passable search result I found with a clean recording: https://www.youtube.com/watch?v=-PXxSHGrF-8 https://www.youtube.com/watch?v=-PXxSHGrF-8