This Standard specifies the mechanical, electrical and functional requirements for the control equipment used for operation of road traffic signals, with the objective of ensuring that, as far as practicable—

(a) controllers from different manufacturers will be physically interchangeable; and

(b) controllers from different manufacturers will have functional compatibility.

NOTE: The requirements of this Standard may not ensure total physical and electrical interchangeability, but should enable a replacement controller to be installed with a minimum of alteration.

The Standard seeks to ensure compatibility between the electronic modules (i.e. the Logic Module, the Flasher Unit and the Site Identification Encoder) mounted in the controller housing. The Standard is necessarily prescriptive in some areas to achieve this purpose.

NOTE: Compliance with this Standard may not ensure full compatibility between Logic Modules and housings of different manufacture since the method of dimming the signal displays is not specified.

The Standard specifies general requirements for the design and construction of traffic signal controllers to meet the needs of users. The Standard specifies technology that has been proven in the field to provide safe and reliable operation.