Cool demo! From the title, I mistakenly thought it might be to make a dial-up compliant modem in JavaScript. But nope, it's a custom toy protocol instead. The

Cool demo! From the title, I mistakenly thought it might be to make a dial-up compliant modem in JavaScript. But nope, it's a custom toy protocol instead. The encoder (sound playback) works in Chrome and Firefox, but the decoder (microphone recording) works in Chrome but not Firefox. Also, the encoder/decoder can't handle non-ASCII text; maybe it is only grabbing the low 8 bits of each UTF-16 code unit.