Described are a system and method to control interface timing andor voltage operations of signals transmitted between devices. An operable digital data storage device is mounted in a fire resistant enclosure. The identifiers extracted from the sessions are grouped in respective identity clusters, each identity cluster identifying a respective entity. The control signals may be used to prevent interference of the CCM signals with the detecting of the cardiac arrhythmia. An optional item may include an attachment component for attaching the apparatus to a piece of construction equipment or farm equipment, such as a tractor. The dielectric structures in the slotted metal pad reduce dishing effect during planarization of the slotted metal pad.