A method for manufacturing a final optical fiber preform via overcladding of a primary preform having a cross section area is disclosed. In one embodiment, the method comprises the first processor disabling an interrupt function on the first pin; and, subsequent to the disabling, interrupting the second processor by driving the first pin to a first logic level and then releasing the first pin to a second logic level. The operation lamp is used to emit light when the operation status of the machine is under operation.