Color codes vary. Modern radios use the same pinout, but different shaped keying on the connectors (your Hubin timer isn't keyed). Center is always +, and is almost always red. Ground is either black or brown, depending on the brand. Signal can be yellow, white, orange, or some other color, but I've never seen one in brown or red.
The nice thing about putting the + lead in the center is that if you connect things backwards you don't blow anything up.