From wikipedia-
Lexicon is considered "the godfather of digital reverb",[4] as one of the early players on the reverb/reverberation market. The company was among the first to produce commercially available digital reverb equipment, beginning in 1978[5] with the Model 224. In 1986, Lexicon released the 480L (costing more than some cars), a successor of the 224XL.
The PCM series was introduced as a smaller, more economical option particularly in live situations where the 480L was too cumbersome for a rack rider. First in the series was the PCM-60 (1984), followed a few years later by the Lexicon PCM-70, the latter adding multi-effects and a digital screen interface. David Gilmour from Pink Floyd used a Lexicon PCM-70 to store the circular delay sounds in songs such as "Shine On You Crazy Diamond" and "Time" in the 1994 The Division Bell Tour.[6]
In the 1990s Lexicon continued the PCM series with two new units, the PCM-80 multi-effects unit and PCM-90 digital reverb. In 1997. they released Model 300 as another iconic multi-effect unit. Lexicon continued the PCM series in the 2000s with new mid-level units including the PCM-96 and PCM-96 Surround, standalone reverb units that easily integrate into DAWs.[7]
Also from the 1990s comes the consumer-level LXP series including the LXP-1, LXP-5, LXP-15 and the LXP-15II, and later the affordable MPX1. A new low-priced reverb series, the MX series, was introduced in the 2000s, with the Lexicon MX200 as the entrance model.