The appropriate product category
- A 1-to-1 full-duplex unbalanced-transfer serial communications using a multi-conductor cable. RS stands for "recommended standard." The electrical specifications are specified. D-sub 25-pin and D-sub 9-pin connectors are specified. There are, however, problems: the transfer speed is slow, the transfer distance is short, communications are easily affected by noise, and only 1-to-1 connections are possible. The RS-422A communications standard was developed as an improved version of RS-232C for unbalanced transfer routes using twisted-pair cable.