A semiconductor package including a semiconductor chip; a base member on which the semiconductor chip is mounted; a plurality of leads formed on the base member, the leads including inner ends electrically connected to the semiconductor chip and outer ends; and an index for identifying locations of specific leads. The compliance of the probes of the probe card apparatus is determined, and an additional, predetermined amount of compliance is designed into the probe card apparatus so that the sum of the additional compliance and the compliance of the probes total the overall desired compliance of the probe card apparatus. Installation of the plug 16 into the jack 18 is simplified because the magnets will guide the plug 16 into the jack 18 once in the proximity thereof The system could also be adapted for use with other similar applications such as coaxial cable 44 connections to replace the threaded and slip-on types of connections known in the prior art. Coil resistance is estimated based on the voice coil voltage, the voice coil current and the velocity values.