Two KL-43s on one screen

Both units share a single AudioContext: whichever side transmits plays through your speakers and is piped directly into the other unit's demodulator, bypassing the microphone entirely. You'll hear the real Bell 103 modem tones; the far side will decode them perfectly every time.

Click a unit to give it keyboard focus, then drive it like the single emulator. Each unit has its own 16-slot keystore (namespaced a / b in localStorage).