Product Series 1600A. Manufacturer Viking Electronics, Inc. A "Call Connected" LED can be initiated manually or automatically. For outdoor installations where the unit is exposed to precipitation or condensation, use model E-1600A-EWP.
Viking likes to mess with people by updating their product line but maintaining the same model numbers. This makes it very difficult to know what works with what, and that becomes costly quickly. Take the 1600A for example. The one I purchased may have been "new" but since it was manufactured in 2005 it is not compatible with the other viking products that are a few years newer. If they had just made the newer product a 1600B or a 1600A-1 or ANY model number difference to let us all know its not the same, we could make informed buying decisions. But they didn't, because they have a problem.