COBRA is a little unique compared to other firing systems as individual cues are fired by toggling independent ground pins through a single shared positive pin as shown below. If you are designing a custom integration, this is no problem, however, the polarity may be reversed from what you are used to. Since igniters are not sensitive to polarity, this should not be a concern when firing fireworks.
The pin-outs on the 6M DB9 port are:
