ADT Customer Service Phone Numbers ADT Toll Free:  Technical Support  Number:  Customer service: 1-800-588-2159 Member Service Center: Emergency Road Service: ADT Sales: 1-888-323-3121 Monitoring: 1-888-238-2727 Sales: 1-866-746-7238 ADT Headquarters Info, Email, Phone number, Website and live chat Information The ADT Corporation is an American corporation that provides residential and small business electronic security, fire protection, and