An image sensing apparatus in which a plurality of lens units can be exchanged and attached. The method according to the invention provides estimated values of noise affecting the radio transmission and of an amount of power which would be carried by each pulse sequence in the absence of noise, respectively, prior to the determination of a threshold value to which the power value is to be compared. The camming surfaces slide into the grooves and move the first and second pipe elements away from one another. As such, signal conductors may be positioned relative to the conductive member such that a uniform impedance is maintained along a signal path throughout the interconnection, reducing noise and reflections.