Bad Idea #1800-CALL-YER-MUM is a dual tone multi-frequency signal generator modeled after telephone communication standards. Each gate input is associated with a DTMF pair that matches the same tone you would hear on an older telephone (Pre-Facetime). There is no trigger conditioning on the inputs which allows the tones to be sustained as drones when a 5V offset is inserted into the jacks. Additionally, this allows for sequences with varying pulse
widths to adjust the duration of each tone.