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NT was a digital memo recording system introduced by Sony in 1992, sometimes marketed under the name Scoopman. The system stored memos using helical scanning on special microcassettes, which were 30 × 21.5 × 5 mm with a tape width of 2.5 mm, with a recording capacity of up to 120 minutes. The Scoopmen cassettes are offered in three versions: The Sony NTC-60, -90, and -120, each describing the length of time (in minutes) the cassette could record.
NT stands for Non-Tracking, meaning the head moves at a shallower slope to that of the tracks on the tape, crossing several during each pass, albeit only reading partial data from each one. By making several passes it is possible to reassemble the complete data for each track, in memory. This considerably reduced the complexity and size of the head, and, therefore, the recorder.
Another feature was Non-Loading, which meant instead of having a mechanism to pull the tape out of the cassette and wrap it around the drum, the drum was pushed inside the cassette to achieve the same effect.
Audio sampling was in stereo at 32 kHz/12 bit and encoded using a form of linear delta modulation called LDM-2.
The Sony NT-2 Digital Micro Recorder, introduced in 1996 and shown here, featured a real-time clock that recorded a time signal on the digital track along with the sound data, making it useful for journalism, police and legal work. Due to the machine's buffer memory, it was capable of automatically reversing the tape direction at the end of the reel without an interruption in the sound. The recorder used a single "AA"-size cell for primary power, plus a separate CR-1220 lithium cell to provide continuous power to the real-time clock. The Sony NT-2, an improved successor to the Sony NT-1 Digital Micro Recorder, introduced in 1992, was the final machine in the series. The NT cassette systems cost more than a DAT recorder in their day, were fragile and relatively unreliable compared to other emerging recording technologies, and being unable to compete soon disappeared from the market. The devices are considered curiosities for collectors.