本标准介绍了在线滤波器（最初，有时仍然称为微型滤波器）的电气和物理特性，该滤波器用于保护声带设备免受25 kHz至12 MHz范围内语音服务上的数字数据高频的影响。它还用于保护语音服务上的数据免受阻抗变化和语音带设备造成的其他有害损害。报警系统和系列堆叠等应用超出了本标准的范围。

This standard presents the electrical and physical characteristics of an In-Line filter (initially, and sometimes still, called a micro-filter), that is used to protect voiceband premises equipment from the high frequencies of digital data over voice services in the 25 kHz to 12 MHz range. It is also used to protect data over voice services from impedance changes and other detrimental impairments caused by voiceband equipment. Applications such as alarm systems and series stacking are beyond the scope of this standard.