Available online
Description
The progranime looks at several features of the I.E.E.E. 488/IEC 625 standard interface system.
The progranime looks at several features of the I.E.E.E. 488/IEC 625 standard interface system.
| Module code and title: | T283, Introductory electronics |
|---|---|
| Item code: | T283; 10 |
| First transmission date: | 01-10-1980 |
| Published: | 1980 |
| Rights Statement: | |
| Restrictions on use: | |
| Duration: | 00:23:56 |
| + Show more... | |
| Producer: | John Stratford |
| Contributors: | David Dack; N. W. Heap |
| Publisher: | BBC Open University |
| Keyword(s): | Computing; Interfacing |
| Footage description: | Nick Hoap introduces the programme. With the aid of diagrams he outlines the limitations of a non-standard interface system in which separate interfaces have to be wired in a star structure to the central computer. David Dack, a design engineer with Hewlet-Packard, then explains how the IEEE 488/IEC 6625 general purpose interface bus makes interconnections much simpler and more flexible. He demonstrates a system using these standard interfaces. With the aid of a diagram showing a general system connected in parallel on the bus structure, Nick Heap explains what is meant by an open collector bus driver. He then demonstrates using a circuit board and animated diagrams. Nick Heap goes on to describe the property of bi-directivality, another property of this type of bus structure. David Dack explains that a general purpose interface bus is an asynchronous bus. He goes on to explain what is meant by this. David Dack, with the aid of an animated diagram, explains the need for a communications 'protocol' between devices on a bus. Then, with more animated diagrams, he explains the mechanism of the two and three wire handshakes. Having explained the two and three wire handshakes in theory, David Dack goes on to demonstrate, using a bus analyser as controller, the sequence of instructions for a voltage measurement. Nick Heap and David Dack point out the constraint of a maximum 20 metre cable run for the bus connections and then demonstrate how these can be extended considerably by use of telephone lines or optical fibre cables. |
| Master spool number: | HOU3387 |
| Production number: | FOUT060P |
| Videofinder number: | 2643 |
| Available to public: | no |
