In June 1975, NEC announced the N7630 Series of magnetic tape units which achieved 6250RPI using the GCR (Group Coded Recording) system. This Series was announced together with the ACOS Series 77 System 500. In April 1976, NEC announced a high speed model, the N7633, together with the ACOS Series 77 System 800 and 900.
Just like the N7620 Series, this Series was compatible with JIS/ISO standard open reel tape (1/2 inch wide, 2400 feet long), and recording capacity was increased by improving recording density and reducing the inter record gap. Laborsaving operation was achieved with an automatic tape mounting mechanism and other features. The cabinet size and appearance were the same as the N7620, but this Series was about 50kg lighter.
| Model name | N7631 | N7632 | N7633 | |
|---|---|---|---|---|
| Recording density(RPI) | 6250(GCR)/1600(PE) | |||
| Inter record gap (inch) | Nominal 0.3,min. 0.28(GCR)/Nominal 0.6,min. 0.5(PE) | |||
| Tape running speed (m/s) | 1.91 | 3.18 | 5.08 | |
| Tape Rewind time(s) | 50max. | 45max. | ||
| Information transfer speed (kB/s) | 468(GCR)/120(PE) | 781(GCR)/200(PE) | 1250(GCR)/320(PE) | |
| Startup time(ms) | 1.9(GCR)/3.0(PE) | 1.5(GCR)/1.9(PE) | 0.95(GCR)/1.5(PE) | |
| External dimensions(mm) | 800(W)×750(D)×1660(H) | |||
| Weight (kg) | Approx. 400 | Approx.450 | ||
| Announced | June 11, 1975 | April 19, 1976 | ||
