QuoteRef: washJ3_1978 ;;Title: Communications interface primer

45 ;;Quote: IEEE 488 has 8-bit data and 8-bit control; if a device is designated a 'listener' it receives data from a 'talker'

QuoteRef: washJ3_1978 ;;45 CAMAC parallel interface standard (IEEE) in 66-wire fully parallel with 24 data bits, or 9-pair byte serial for transmitting 24 bit words by threes, or 2-wire serial interface. Devices organized into standard remote interface units called crates.

47 ;;Quote: a communications protocol defines data formatting, error checking, priorities, and device assignments; each manufacturer uses a different one

60 ;;Quote: PIDCOM uses serial links and ASCII to communicate with its analog controllers

QuoteRef: washJ3_1978 ;;61 "Regardless of which controller is used, every CAMAC crate has an 86-point connector called a Dataway. This Dataway can accommodate up to 25 modules along with a power supply. Any module made to CAMAC specifications-- from A/D multiplexers to color CRT display drives--can plug into the CAMAC crate, regardless of its manufacturer.

QuoteRef: washJ3_1978 ;;62 "Ease of use along with CAMAC's speed make it a top of the line interface. It is, however, expensive. /COMAC 2-wire serial highway can transmit up to 5 megabaud, making it of the fastest serial interfaces available/

QuoteRef: washJ3_1978 ;;63 SDLC and HDLC data link protocols for networking. eg used in Honeywell's TDC-200 data highway (well almost the same).

64 ;;Quote: SDLC message frame consists of fields giving destination, message type, error-checking, and data; can send via any station

QuoteRef: washJ3_1978 ;;64 "SLDC and HLDC are by far the most efficient protocols available today...However, data link protocols are more expensive to implement because an intelligent controller must be installed in each remote station.

64 ;;Quote: IEEE 488 instrument bus is very good for small systems since modules just plug together