Extron Electronics MVC 121 Plus User Guide - Manual (Page 20)

Digital Input Port
The three-pin digital input port (Digi In) is used to monitor or drive TTL level digital signals.
The port consists of three input pins with the fourth pin being used as a ground providing
three inputs total. The DSP Configurator software provides a selection of functions from a
list, to be loaded to the MVC 121 Plus.
NOTE: The digital input connectors are used to mute or unmute the input signal using
a contact closure device. SIS programming commands cannot mute or unmute
the input signal while the digital input ports are connected. The digital input
ports are “off” and not configured by default.
1. From the main structure menu, click Tools > Configure Digital Inputs to access the
Config utility.
2. Select the digital input to configure.
MVC 121 Plus • Operation 14