You probably know this, but the emitter has to be placed precisely in front of the window on the device. Which device is not responding? Are you sure the emitter is in the right place? A bright flashlight will often reveal an opaque spot smaller than a dime that you have to nail with the emitter location.

And CCP software has to be set to the same RF ID as the base station.

AND you sometimes have to move the antenna around, even collapse the antenna to the folded up position to prevent interference from nearby devices, especially cable boxes. Make sure the activity LED is not glowing in the slightest when no button is pressed.