SAE EIA 408:2016-06-16

This standard applies to the interconnection of data terminal equipment and numerical control equipment at the tape reader interface. The data terminal would typically be connected to a remote data source/sink such as a computer.

This standard defines:

This standard is applicable for the interchange of signals when used in conjunction with electronic equipment, each interchange circuit of which has a single return (signal ground) that can be interconnected at the interface point.

Figure 1.1, typical installation, shows how this standard should be applied to a typical tape reader interface of numerical control equipment.