3.81-mm (0.150~in)-wide magnetic tape presents the minimum requirements for the mechanical and magnetic interchangeability of the cassette between information processing systems, using the physical recording density of 394 ftpmm (10 000 ftpi). The cassette is of the twin hub coplanar type, loaded with 3.81-mm (0.150-in)-wide magnetic tape. Access holes are provided for, and the tape is transported between hubs by external reel motors. Features are provided for the use of external tape capstan(s), tape position sensing, and external tape guiding. This standard applies to the cassettes used for data interchange.