The Transformer Protection System M-3311A provides protection, control, monitoring and user interface functions for two, three or four-winding transformers. Includes restrained and unrestrained differential protection, overcurrent protection, and optional voltage, and underfrequency protection. Multiple setpoint groups and user-implementable logic schemes provide flexibility. Dual RS-232 ports and an RS-485 port provide user-interface capabilities. Optional modules include the HMI Module for front-panel operation, the Target Module to indicate trip target status and redundant power supply. The M-3311A can be purchased as a differential and overcurrent relay or with the Optional Voltage Protection Package. The M-3826 IPScom® Communications Software is included for direct serial or remote communication access. Waveform data can be downloaded using IPScom®, while the M-3801D IPSplot® PLUS Oscillographic Analysis Software allows for plotting and printing of the downloaded oscillographic data.