APPENDIX B: Electrical Interfaces
Appendix B. Electrical Interfaces
RS-530
RS-530 (EIA-530) compatibility means that RS-422 signal levels are met, and the pinout for the DB25 connector is specified. The EIA (Electronic Industry Association) created the RS-530 specification to detail the pinout, and define a full set of modem control signals that can be used for regulating flow control and line status. The RS-530 specification defines two types of interface circuits. Data Terminal Equipment (DTE) and Data Circuit-Terminating Equipment (DCE). The USB Single-Port Hub (RS-422/485) is a DTE interface.
RS-422
The RS-422 specification defines the electrical characteristics of balanced voltage digital interface circuits. RS-422 is a differential interface that defines voltage levels and driver/receiver electrical specifications. On a differential interface, logic levels are defined by the difference in voltage between a pair of outputs or inputs. In contrast, a single-ended interface, for example, RS-232, defines the logic levels as the difference in voltage between a single signal and a
