HP 10343B Operating Manual

The comparitor outputs are connected directly to the interface outputconnectors J3 and J4. Through these connections the logic analyzer has adirect connection to the SCSI Bus.Parity check is accomplished with U3. U3 is tied to the data lines DBOthrough DB7 and DBP (Parity). The output of U3 is run through parityswitch S2 so that this signal may be switched off when the SCSI Bus isn’tusing parity.The output of the parity device U3 goes high if odd parity is not met. Ahigh output is considered an error condition and is displayed on the logicanalyzer screen as a "* PARITY ERROR *" when S2 is turned on.All of the SCSI Bus lines are connected to LED indicators to allow theuser to view the status condition of the SCSI Bus at a glance. TheseLED’s are driven with open collector buffers U2, U21, U22, and Ql.Additional InformationA-6