Custom Engineering is a U.S.-based consulting engineering firm founded in 1974, providing engineering design services for commercial, industrial, institutional, and rehabilitation projects. Its core disciplines include mechanical, electrical, plumbing, lighting, IT/low-voltage, and commissioning services. The IT/Low Voltage practice includes Access control, Video surveillance / CCTV, Fire alarm systems, Intrusion and duress alarms.

Now a Custom Engineering Company, TIE Consulting specialises in the planning, design, and construction management of low-voltage systems. It has significant involvement in electronic security and low-voltage systems, including Access control, Video surveillance, Integrated security, Intrusion alarms, Duress alarms, Weapons detection, Emergency/security intercommunications, Fire alarm systems, Emergency communications, and public-safety systems.