Construction of The Video Compact Cassette
Despite the name, VCCs are marginally larger than VHS cassettes — 5 mm shorter, but a millimeter thicker and 6 mm deeper. They have two co-planar reels containing half-inch (12.5 mm) wide chromium dioxide magnetic tape. The format utilized only a quarter-inch (6.25 mm) of the half-inch tape on a given side, and so it is occasionally referred to erroneously as a quarter-inch tape format despite its physical tape width.
While VHS and Beta tapes have a break-off tab to protect recordings from erasure (as in audio Compact Cassettes and, once broken, the cavity left by the missing tab must be covered or filled before the tape can be reused), VCCs employ a more elegant solution: a switch on the tape edge can be turned to red to protect the recordings, and back to black/brown (depending on the colour of the cassette housing) to re-record. The switch covers/uncovers a hole along the tape edge, which is detected by a sensor in the machine.
The tape edge features six such holes along each side of the tape, detected by sensors on the cassette's underside. The left-hand cluster includes the write-protection hole. The right-hand cluster of three is used (by various permutations of open/closed status) to tell the machine the total tape running time. This was employed in later machines such as Grundig's Video 2x4 Super to provide a real-time tape counter: upon insertion of the tape the machine move the tape forward and then backward by a small amount and monitor the comparative angular speed of the reels. This is looked up in a data table for the known total tape length and the hours and minutes used are then displayed. A similar technique was later used on Video8, MiniDV and MicroMV cassettes. Some later VHS machines also featured this ability although it did not work with VHS-C cassettes. NOTE: When Grundig began marketing VHS recorders, its GV280 machine employed barcoded stickers attached to the tape edge, indicating the total tape length to the machine so that it could calculate the time used.
Read more about this topic: Video 2000
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