as by the tci timeline algorithm upon tissue contact detection digital interface 32 also directs data capture analysis display and storage in a pre programmed fashion per the tci timeline the interface 32 consists of two components one of which is located in a system main monitoring unit the other of which is located in a pci bus slot in a system computer digital interface 32 employs stimulus controller 30 which shapes the current provided from the current source 22 into stimuli of pre programmed intensity duration and having a pre selected temporal pattern the stimulus controller 30 is driven by digital interface 32 which stores stimulus paradigms in non volatile memory and initiates the stimulus paradigms as pre programmed within the tci timeline algorithm digital interface 32 also controls functions relating to data acquisition analysis display and storage through its connection with the cpu for stimulus output 2 3 or both digital interface 32 may be configured to input measured values of stimulus circuit impedance and make pre programmed adjustments of stimulus intensity based upon impedance values it is anticipated that stimulus output 1 will be used with a flush tip stimulus probe for which such an application is not necessary in fig1 impedance detection circuit id 1 40 is included to provide an indication of tissue contact and to measure nominal stimulus circuit impedance detection of tissue contact.