AS 2412-1980

1 - AS 2412-1980 INFORMATION INTERCHANGE ON 3.81 mm (0.150 in) MAGNETIC TAPE CASSETTE AT 4 CPMM (100 CPI), PHASE ENCODED AT 63 ft
4 - PREFACE
6 - 1 SCOPE AND FIELD OF APPLICATION
6 - 2 DEFINITIONS
6 - 2.1 magnetic tape:
6 - 2.2 reference tape cassette:
6 - 2.3 secondary reference tape cassette:
6 - 2.4 reference field:
6 - 2.5 test recording current:
6 - 2.6 signal amplitude reference tape cassette:
6 - 2.7 standard reference amplitude:
6 - 2.8 average signal amplitude:
6 - 2.9 in contact:
6 - 2.10 track:
6 - 2.11 bit density:
6 - 2.12 position of flux transitions:
6 - 2.13 leader:
7 - 2.14 erasing field:
7 - 2.15 print through:
7 - 2.16 reference alignment cassette
7 - 2.17 typical field:
7 - 3 ENVIRONMENT AND TRANSPORTATION
7 - 3.1 Testing environment
7 - 3.2 Operating environment
7 - 3.3 Transportation and storage environment
7 - 3.4 Transportation
7 - 4 CHARACTERISTICS OF TAPE
7 - 4.1 Mechanical properties
8 - 4.2 Tests of magnetic properties
9 - 4.3 Electrical surface resistance
9 - 5 TAPE CASSETTE
9 - 5.1 Identification of cassette sides
9 - 5.2 Mechanical characteristics
9 - 5.3 Basic specifications
10 - 5.4 Labelling of tape cassette
11 - 5.5 Magnetic properties of the cassette housing
11 - 6 RECORDING
11 - 6.1 Method of recording
11 - 6.2 Equipment
11 - 6.3 Density of recording
11 - 6.4 Flux transition spacing
11 - 6.5 Signal amplitude
11 - 6.6 Number of elongated gaps
12 - 6.7 Alignment error
12 - 6.8 Tape winding torque
12 - 6.9 Residuals of previous recordings
12 - 7 FORMAT
12 - 7.1 Number of tracks
12 - 7.2 Track dimensions
12 - 7.3 Track designation
12 - 7.4 Use of tracks
12 - 7.5 Location of characters on the tracks
12 - 7.6 Sequence of recording
12 - 7.7 Code
12 - 7.8 Sequence of characters
12 - 7.9 Data block
13 - 7.10 Control block
13 - 7.11 Gaps
13 - 7.12 Preamble and postamble
13 - 7.13 Cyclic redundancy check (CRC)
24 - ANNEX A - LAYER-TO-LAYER ADHESION
25 - ANNEX B - MEASUREMENTOF LIGHT TRANSMITTANCE
25 - B.1 INTRODUCTION
25 - B.2 DESCRIPTION OF THE TEST DEVICE
25 - B.2.1 Radiation (light) source
25 - B.2.2 Optical path
25 - B.2.3 Measuring mask geometry
25 - B.2.4 Photoelectric cell
25 - B.2.5 Measuring equipment
26 - B.3 TEST PROCEDURE
26 - B.4 GUIDANCE ON CONSTRUCTION

Specifies essential characteristics of 3.81 mm magnetic tape cassettes using the 7-bit coded character set. The recording system specified uses the 31.5 bits per millimetre phase encoded recording method. Technically identical with ISO 3407.

This International Standard specifies the characteristics of a 3,81 mm (0.150 in) magnetic tape cassette to provide data interchange and physical interchangeability between information processing systems utilizing the ISO 7-bit coded character set (ISO 646) and, where required, its extensions (ISO 2022). The cassette is of the twin hub coplanar type, loaded with a 3,81 mm (0.150 in) wide magnetic tape for digital recording using the 31,5 bits per mm (800 bpi) phase encoding method. The direction of magnetization is in the longitudinal direction of the tape.NOTE - Throughout the remainder of this International Standard for the sake of simplicity the recording density is stated as 32 bpmm, (800 bpi) nominal.This International Standard applies to cassettes and data used for interchange. Where it applies for testing only, this is specifically stated.

Reconfirmed 1989