I have BRK model H 210640 old one over 25 years, my unit system contained with four (4) wires Green, white , black , etc. It seem the system connect to alarm system. Started with short beeps and then with long beep. Please let me know if needs to be replace with new one and where I could purchase or your firm can provide for me . My e-mail is : mshahangian@aol.com or/ for delivery addressis : Mahmoud Shahangian 4 Hazelhurst Drive Voorhees, NJ 08043. Tel: 646-531-2653 Thank you