JV
From this page on DigitalSpy Forums - https://forums.digitalspy.com/discussion/581268/teletext-signal-strength-test
Does anybody remember the network ID that appeared on some TVs at the bottom of the screen when you switched channels in the analogue days? I think it was something to do with data in the teletext header although it didn't exactly match it. For example it would say "BBC ONE" on BBC1, it would give the regional name on ITV and on Channel 4 it would come up with "Channel 4 Television".
I also remember an old TV my grandparents had which had a "Clock" button which displayed the time and was taken from the teletext data - once when Ceefax was off air displaying this page:
http://teletext.mb21.co.uk/gallery/ceefax/cx_off-air.gif
pressing the Clock button on the remote brought up the message "SEE P100"!
James Vertigan
Founding member
From this page on DigitalSpy Forums - https://forums.digitalspy.com/discussion/581268/teletext-signal-strength-test
Quote:
The clock-cracker was a test that the 'clocking-frequency' didn't drift for the duration of the (otherwise unused) vertical interval line carrying the telext data.
The decoding clock was locked at the beginning of the line (much like the 'colour burst' locked the PAL crystal frequency and phase) and then ran 'free' for the duration of the line.
The decoding clock was locked at the beginning of the line (much like the 'colour burst' locked the PAL crystal frequency and phase) and then ran 'free' for the duration of the line.
Does anybody remember the network ID that appeared on some TVs at the bottom of the screen when you switched channels in the analogue days? I think it was something to do with data in the teletext header although it didn't exactly match it. For example it would say "BBC ONE" on BBC1, it would give the regional name on ITV and on Channel 4 it would come up with "Channel 4 Television".
I also remember an old TV my grandparents had which had a "Clock" button which displayed the time and was taken from the teletext data - once when Ceefax was off air displaying this page:
http://teletext.mb21.co.uk/gallery/ceefax/cx_off-air.gif
pressing the Clock button on the remote brought up the message "SEE P100"!
Last edited by James Vertigan on 17 August 2017 7:41am - 2 times in total