This converter has 16 GPI inputs (general purpose interface) arranged on two 9 pin D sockets. It can output MIDI messages as Notes, Controllers (CCs) or Program Changes. In the following description references to MIDI note numbers also applies to Controller Numbers or Program Numbers if that is the output mode currently in use.

Each block of 8 inputs can be assigned a starting MIDI note number and subsequent inputs follow on consecutive note numbers. (default for first block is 36-43, and for the second block is 44-51
Each block of 8 inputs can be set whether note offs are sent when the switches open (default =yes) NB Off messages do not apply to Program Changes
The MIDI transmit channel for all inputs can be set (range 1 to 16, default =1)
The debounce value for all switch inputs can be set (range 1 to 100 milliseconds - default =10mS)

The inputs are arranged with internal pullups, so that shorting that input to ground will send the appropriate MIDI note-on message - releasing the short to ground will send a note-off message (unless disabled).

The D socket inputs are arranged with pins 1-8 as inputs 1-8 (or 9-16) and pin 9 as ground.

The GPIM-16 has two MIDI out sockets which both carry identical MIDI information. MIDI arriving at the MIDI input is merged with the data generated by the switch inputs and sent to the MIDI outs.

The unit is supplied complete with a power supply (UK, EU and US versions available) connected by a locking power plug.

Editing of parameters is acheived by use of push buttons in conjunction with the LED display.

In order that settings cannot be accidentally changed, edit mode can only be enabled using a recessed push button.