The ABB SPA-ZC 22 is a highly reliable communication interface module specifically engineered for Substation Protection and Automation (SPA) systems. Serving as an advanced optical repeater, this module facilitates seamless data transmission across RS 485 and SPA bus protocols. It offers versatile configuration options, including Master/Slave operation and multiple optical repeater modes (such as 2B0M, 1B1M, 0B2M, 1B1M/BM, and 1B1M/MB) which are easily selectable via integrated DIP switches (S1, S2). Designed for broad compatibility in demanding industrial environments, the SPA-ZC 22 features dedicated serial ports for SPA/RS485 and RS 232 connections. Furthermore, it supports a wide-ranging auxiliary voltage input that accommodates various AC and DC power supplies. Front-panel status LEDs (Power, Aux, INT, Tx, and Rx) ensure real-time monitoring of power and communication activities, making it an essential component for robust substation network integration.