device for connecting between of them communication equipment and data terminal equipment data

摘要

An interface for connecting data terminal equipment (DTE) to data communication equipment (DCE) is provided which requires no modification to an existing and widely accepted DCE connector and yet which permits data communication according to more recently adopted functional interface standards through the same DCE connector. Specifically, in a single 25-position interconnection configuration for DTE, an interface is provided which supports (1) the EIA Standard RS-232C interface with unbalanced generators and receivers at generally established RS-232C pin assignments at a DCE terminal junction; (2) an RS-449-type interface with balanced generators and receivers with pin assignments at locations incapable of being confused with RS-232C interface connections at a DCE terminal junction; and (3) an RS-449-like interface with balanced generators and receivers in a variety of multiple-point applications. The DTE portion of the interconnection according to the invention includes only an external cable and connector which is provided to the DCE terminal junction. In an RS-232C interconnection, the external cable includes connections jumpering to ground one input of each balanced receiver to allow use of the receiver as an unbalanced RS-232C-type receiver. In both balanced and unbalanced configurations, the cabling to the DCE includes the minimum number of electrical conduits necessary for DTE communication.