The Tesira EOC-4 is an expander card with 4 analog output channels for use with Tesira EX-MOD device. The EOC-4 is one of three optional cards that can be mounted in Tesira EX-MOD. Each EOC-4 provides 4 channels of line level audio output. The outputs are electrically balanced and provided on plug-in barrier strip connectors. Software control of each output includes mute, level, signal invert and full-scale output reference. The modular card shall provide 4 balanced outputs on plug-in barrier strip connections. Software configuration and control for each output shall include mute, level, signal invert and selectable output reference level.