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Model 1630A/D/G
An HP-113 Overview
INTRODUCTION
The HP Interface Bus (HP-113) provides an interconnecting channel for data transfer between devices on the
HP-IB .
The following list defines the terms and concepts used to describe HP-113 (bus) system operations .
HP-IB SYSTEM TERMS
1 . Addressing - The characters sent by a controlling device specifying which device sends information
on the bus and which device(s) receives the information.
2. Byte - A unit of information consisting of 8 binary digits (bits) .
3. Device - An unit that is compatible with the ANSI/IEEE 488-1978 Standard .
Appendix B
An HP-1B Overview
4 . Device Dependent -A response to information sent on the HP-113 that is characteristic of an individual
device's design, and may vary from device to device .
5 . Operator - The person that operates either the system or any device in the system .
6 . Polling - The process typically used by a controller to locate a device that needs to interact with the
controller . There are two types of polling :
" Serial Poll - This method obtains one byte of operational information about an individual device in
the system . The process must be repeated for each device from which information is desired .
Parallel Poll - This method obtains information about a group of devices simultaneously .
INTERFACE BUS CONCEPTS
Devices which communicate along the interface bus can be classified into three basic categories .
1 . Talkers - Devices which send information on the bus when they have been addressed .
2. Listeners - Devices which receive information sent on the bus when they have been addressed .
3. Controllers - Devices that can specify the talker and listeners for an information transfer . Controllers
can be categorized as one of two types:
" Active Controller - The current controlling device on the bus. Only one device can be the active
controller at any time .
System Controller - The only controller that can take priority control of the bus if it is not the current
active controller. Although each bus system can have only one system controller, the system can
have any number of devices capable of being the active controller .
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