Roadmaster LED Signboard
The NODE has a Roadmaster RRDS100H LED Signboard. This page details what we know about it.
Programming occurs over IR, and it looks like the device reports out what it's displaying on a single LED on the back as well. The small board with the IR demodulator and red (IR?) LED on it is labeled "3-750 B.pcb". The 4-wire connector to it breaks out: two pins (1 [square pad] and 3) go to the IR demodulator, pin 2 goes to the LED, and pin 4 seems to be ground.