While the usable bandwidth for AM modulated carrier is obviously smaller than for visible light, it does not matter in any meaningful way, because it is still s

While the usable bandwidth for AM modulated carrier is obviously smaller than for visible light, it does not matter in any meaningful way, because it is still significantly larger than anything that could be processed by today's electronics. There are different protocols specified for IR transmissions: - IrDA - master-to-multiple-slaves, directly amplitude modulated IR with RZ coded 8N1 asynchronous serial port frames frames (which is directly supported by reasonably modern UARTs) with HDLC-like protocol suite on top. This supports standard serial port speeds up to 115k2 and has extensions with different modulation schemes that go up to 512Mbps, with 4Mbps variant being generally supported by most PC hardware. It serves mostly same purpose as bluetooth, protocol stack is largely similar and for long time it was in practice significantly faster than bluetooth. - Above mentioned 802.11 IR Physical layer - IIRC something like 1 or 10 Mbps, protocols same as for 802.11, there probably were no commercially successful implementations. - Various standard, "standard" and completely proprietary protocols for remote controls. Hundreds to thousands bps, typically using few tens of kHz carrier wave that gets modulated on to the IR.