Abstract: An electrical coupler which is capable of being easily assembled into a main unit for electrically detachable interconnection of an external unit to the main unit. The coupler includes a dielectric header which carries an array of first terminal ends and an array of second terminal ends which are engageable with an arrays of first contacts of the main unit and an array of second contacts of the external unit for establishing an electrical interconnection. The header is made of a rigid material which integrally supports the array of the second terminal ends to define thereat a terminal connector responsible for detachable connection to the external unit. The header is molded to have a mount flange as an integral part for securely fixing the header to an enclosure of the main unit.