This plugin enables PCStage to support the MIDI Show Control protocol with events and triggers, in the same way that it does internally with simple channel-specific messages. It is assumed that the reader is familiar with MSC. The MIDI input and output devices used are those open in PCStage, which routes messages to and from the plugin, and the plugin's data is saved in the same directory as the current PCStage production, with a '.pcs_msc' filename extension.

The plugin presents three pages, for events, triggers, and a Monitor which shows all incoming and outgoing MSC messages, including incoming ones which do not fire a trigger.

Events are assigned names which are used by PCStage to execute them (see below), and can specify any command-specific data lists, including parameter markers (asterisks) which are replaced by numeric parameters when the event is executed; these parameters are supplied either by PCStage or, interactively, by the user if executed directly from the plugin.

Triggers also specify data lists which can include asterisks, but in this case they are wildcards, which indicate that any data is to be accepted at that location in the message. Each trigger has a PCStage command which is executed when the trigger matches an incoming MSC message, and a cue filter which can be used in the same way as with PCStage's internal triggers.

For the purpose of handling triggers, MSC (and thus PCStage) has the ID and belongs to the ID groups specified in the Triggers page, and also accepts the "all-call" ID of 127.

The data lists used in events and triggers consist of comma and/or space-separated items, each of which can be a decimal number (0-127), a hex number ($00-$7F) or an asterisk (parameter or wildcard).

MSC supports a single PCStage plugin event command:

    Event <name> [<param>, <param>...]