User Manual DDS200 Digital Demodulation System 070-9952-00

Appendix B: IEC/IEEE-Bus InterfaceSRQ (Service Request),Active LOW enables a device to send a service request to the controller.REN (Remote Enable)Active LOW allows switchover to the remote-control mode.EOI (End or Identify)In connunction with ATN, this line has two functions: active LOWdenotes the end of data transmission with ATN = HIGH and active LOWtriggers a parallel poll with ATN = LOW.Handshake bus with three linesDAV (Data Valid)Active LOW signals that a valid data byte is on the bus.NRFD (Not Ready For Data)Active LOW signals that one of the connected devices is not ready toaccept data.NDAC (Not Data Accepted),Active LOW until the connected device has accepted the data on the bus.Table B–1: Bus LinesIEC/IEEE-488 Connector Pin No. Bus Line Pin No. Bus Line1 DIO1 13 DIO52 DIO2 14 DIO612 11 10 9 8 7 6 5 4 3 2 1 3 DIO3 15 DIO74 DIO4 16 DIO85 EOI 17 REN6 DAV 18 GND(6)7 NRFD 19 GND(7)8 NDAC 20 GND(8)24 23 22 21 20 19 18 17 16 15 14 139 IFC 21 GND(9)10 SRQ 22 GND(10)11 ATN 23 GND(11)12 Shield 24 Logic GNDB–2 DDS200 Digital Demodulation System User Manual