Omrom programmable terminal

AFAIK, the first commercially available modem for voice-grade PSTN to achieve 9600 bps or more was the Telebit Trailblazer, introduced in 1985. It was half-duplex at approximately 18,000 bps (peak) with a low bit rate reverse channel. The firmware automatically did line turnarounds based on buffer depths, so it simulated full duplex but with relatively high latency. The Trailblazer used proprietary Packetized Ensemble Protocol (PEP), which used up to 512 narrow-band carriers. It was a forerunner of OFDM modulation, which is now used for 802.11a/g/n and many other high performance data radio applications. The Trailblazer is a 6 baud modem! :-) A baud is a symbol per second, NOT a bit per second. A symbol can encode multiple bits, and in PEP modulation a symbol encodes thousands of bits. For comparison, a V.32 9600 bps modem actually communicates at 2400 baud, with four bits per symbol (16-point constellation).