ESDi is a PA intercom program for Windows 95 or better. Anyone with a PC running windows, audio input source (e.g. microphone/CD/mono mix), speakers/headset, and a local area network (LAN) connection, should be able to use this application. An instance of the software can be called directly or as part of a grouping. Groups could be PCs in the same department or people working on the same project. Pre-recorded messages can be broadcast.