User Manual DDS200 Digital Demodulation System 070-9952-00

Appendix B: IEC/IEEE-Bus InterfaceThe DDS200 Digital Demodulation Sysem is fitted with an IEC/IEEE-businterface as standard. The connector for the IEEE-488 bus is located on the rearpanel. A controller can be connected for remote control, using a shielded cablefor the connection.Interface CharacteristicsThe EC/IEEE-bus interface has the following characteristics:8-bit parallel data transmissionBi-directional data transmissionThree-wire handshakeHigh data transmission rate, max. 350 Kbyte/sConnection of up to 15 devicesMaximum length of connecting cables: 49 feet (15 m); length of singlecable: 6 feet (2 m)Wired OR links when several devices are connected in parallelBus LinesThe following are descriptions for each of the bus lines for the IEC/IEEEinterface (see Table B–1): Data bus with 8 lines, DIO 1 to DIO 8Transmission is bit-parallel and byte-serial in ASCII/ISO code. DIO 1 is thelowest-significant and DIO 8 the highest-significant bit.Control bus with 5 linesIFC (Interface Clear)Active LOW resets the interfaces of connected devices to a definedinitial condition.ATN (Attention)Active LOW signals the transmission of interface messages; inactiveHIGH signals the transmission of device-dependent messages.DDS200 Digital Demodulation System User Manual B–1