提供1/2英寸9磁道磁带的格式和记录规范，该磁带用于信息处理系统、通信系统和使用ANSI X3的相关设备之间的信息交换。4:1977，美国信息交换国家标准代码（ASCII）。只处理磁带录音，支持并补充ANSI X3。40:1983，信息交换用未记录磁带（9轨800 CPI，NRZI，1600 CPI，PE和6250 CPI，CGR）。

Provides specifications for format and recording for a 1/2 inch, 9-track magnetic tape to be used for information interchange among information processing systems, communication systems, and associated equipment utilizing ANSI X3.4:1977, American National Standard Code for Information Interchange (ASCII). Deals solely with recording on magnetic tape and supports and complements ANSI X3.40:1983, Unrecorded Magnetic Tape for Information Interchange, (9-Track 800 CPI, NRZI, 1600 CPI, PE and 6250 CPI, CGR).