the knock board is a circuit board (seperate from main ECU PCB) mounted in the top-right hand corner of DOHC Vtec ECUs having a Knock Sensor. The Knock Board is responsible for processing the essentially auditory signal from the Knock Sensor and triggering an alarm if Pre Ignition is detected. In their stock form, the honda Knock Board might be useful for detecting knock from bad gas, although this is rather questionable.

Conventional wisdom says honda knock boards suck for detecting detonation while boosting. Conventional wisdom says honda knock boards freak over forged internals and pull timing during normal operation.

If you use a program that has the knock sensor disabled in an ECU that has a knock board present, the ECU will ignore the Knock Board's presence - in fact you can remove the Knock Board without any noticeable effect.

KnockBoard Patents (Knock Board on P72 has patent numbers on it which I couldn't resist looking up):

*4,825,364 - Monolithic data processor with memory refresh

4,942,561 - Delay time measuring device

*4,896,260 - Data processor having integrated circuit memory refresh

*4,829,419 - Microcomputer control of machines

4,954,951 - System and method for increasing memory performance

*4,120,583 - High registration photomask method and apparatus

*4,121,284 - Computerized system for operator interaction

*4,686,622 - Computer system architecture using serial communication

4,531,182 - Machine control system operating from remote commands

*4,396,976 - System for interfacing a computer to a machine

*4,371,923 - Computer system architecture

*Shared patents with HP Laser Jet? 5L

Details for each patent can be found at: http://patft.uspto.gov/netahtml/srchnum.htm