Dortronics Herculite door U-Bracket receiver housing Electrical/Doorbells & Intercoms Manufacturer: Pacific Electronics Buttons: Momentary action button marked talk,listen, and door ⚠️ Important Compatibility Notice This product is the 4-wire version of Pacific Electronics’ intercom line. Although it looks nearly identical to 3-wire and 6-wire models, it is not interchangeable with them. Before placing your order, please ensure your current intercom uses exactly 4 wires at the entrance station. If your system uses 3 or 6 wires, this model will not work. Choosing the correct version helps ensure proper functionality and avoids the need for returns or replacements. Need help identifying your system? Contact us with a photo of your wiring setup and we’ll assist — fast and free.