29-04-2016, 01:12 PM
Ah! What's in a name?
When we were developing our own system at the Stock Exchange, we had to use the rather clumsy term 'wired teletext' (to differentiate it from 'broadcast teletext') because BT used the term Viewdata for their own service.
However, as development proceeded, BT decided that they ought to register Viewdata as a trade mark - but were turned down!
The reason, apparently, is that because viewdata says exactly what it does, it must be generic, and you can't register a generic term as a trade mark! Thus Prestel was born and we could call our TOPIC (Teletext Output Price Information Computer) system a viewdata system! (The TOPIC name stemmed from an existing system to which it was essentially a bolt-on extra and that was known as EPIC - Exchange Price Information Computer)
Our system differed from Prestel in a number of ways. Firstly it primarily operated over private circuits (with dial-up as a back up) and was also much faster in the City area because we used 9600bps baseband modems - 8 times faster than the 1200bps dial-up speed - but these required DC circuits to operate and circuits which extended beyond BT's City boundary were AC coupled. However, the ability to refresh a page in a second or less, dependent on the amount of data, helped it compete alongside the 22 channel TV system which had been operating for 10 years and which had 'instant' channel change via a push button selector.
We also added a few extra wrinkles to the standard specification by using the CAN code, for exampler - CAN means delete to the end of the row, carriage return & line feed, all with the one character!
This was particularly useful on the price pages because each line consisted of Stock Name, previous day's closing price and then changes occurring during the day. Many stocks trade at quite low levels, so those rows had a lot of blank space on the right.
It also completely confused any decoder following the Viewdata Specification, in addition to a different password structure, this making it difficult to attempt to high-jack the service for free!
When we were developing our own system at the Stock Exchange, we had to use the rather clumsy term 'wired teletext' (to differentiate it from 'broadcast teletext') because BT used the term Viewdata for their own service.
However, as development proceeded, BT decided that they ought to register Viewdata as a trade mark - but were turned down!
The reason, apparently, is that because viewdata says exactly what it does, it must be generic, and you can't register a generic term as a trade mark! Thus Prestel was born and we could call our TOPIC (Teletext Output Price Information Computer) system a viewdata system! (The TOPIC name stemmed from an existing system to which it was essentially a bolt-on extra and that was known as EPIC - Exchange Price Information Computer)
Our system differed from Prestel in a number of ways. Firstly it primarily operated over private circuits (with dial-up as a back up) and was also much faster in the City area because we used 9600bps baseband modems - 8 times faster than the 1200bps dial-up speed - but these required DC circuits to operate and circuits which extended beyond BT's City boundary were AC coupled. However, the ability to refresh a page in a second or less, dependent on the amount of data, helped it compete alongside the 22 channel TV system which had been operating for 10 years and which had 'instant' channel change via a push button selector.
We also added a few extra wrinkles to the standard specification by using the CAN code, for exampler - CAN means delete to the end of the row, carriage return & line feed, all with the one character!
This was particularly useful on the price pages because each line consisted of Stock Name, previous day's closing price and then changes occurring during the day. Many stocks trade at quite low levels, so those rows had a lot of blank space on the right.
It also completely confused any decoder following the Viewdata Specification, in addition to a different password structure, this making it difficult to attempt to high-jack the service for free!
