Signal Stat est bien une marque (cf. ci-dessous) mais pour la signification d'"interchange" il faudrait plus de contexte... (ou plus de connaissances sur les camions!)

Truck-Lite Co Inc has completed its acquisition of the assets of Signal-Stat Lighting Products, a division of Federal Mogul Corp, said Stephen Davis, president of Penske Transportation Components, the parent company of Truck-Lite. Terms of the acquisition were not disclosed.

Acquired by Federal Mogul in 1986, Signal-Stat manufactures scaled and bulb-replaceable lighting, turn signal switches, emergency lighting, and vehicle safety accessories. The company mainly serves the North American heavy-duty and commercial vehicle market. Employing more than 300 people, Signal-Stat has facilities in El Paso and Brownsville TX and Logansport IN.