If you look close enough at the display, you can see quite clearly that they are made up of individual segmants. These are invidividual painted segmants that rotate round to form characters as required. If they were dot matrix, look at how for example aptis tickets were printed. Each character was made up of dots.
I think you'll find we are talking about the same basic design and i hope to be able to explain more clearly in this post.
I am not talking about a display made up of LED's but a sign consisting of a matrix of
lights or mechanical indicators arranged in a rectangular configuration (other shapes are also possible, although not common) such that by switching on or off selected lights, text or graphics can be displayed.
A dot matrix controller converts instructions from a processor into signals which turns on or off lights in the matrix so that the required display is produced.
Hence why on the Railway they are called Dot Matrix Displays.
Networkers were fitted with this type of system when new - some still do have this type of Display. A Dot matrix display is not made of up dots i agree here too, but you cannot confuse a Dot Matrix printer (as per Aptis) with a Dot Matrix Display.
This one clearly shows the segmants (look at the A for example and you can see the lines clearly on this which make up this letter) which make up the letters. Where the white dot is says to me that there is obviously part of the display missing and the "Backlight" is showing through.
Again i agree - as per the picture on my last post.
This used to happen frequently with our olympian buses which were fitted with Transign roller displays and worked in a similar way - sometimes a roller would stick or fall out and then show the backlighting behind. The older NSE Style "Digital" clocks work in the same way if you have noticed.
I agree again - however, on the Railways these displays were known as Dot Matix - even on the clock, as i said in my last post read this link and you will understand what i mean
http://en.wikipedia.org/wiki/Dot_matrix_display
Many people do refer to them as dot matrix, but if this was the case then they would be made up if a collection of dots, not segments as can be seen on this photo.
Yes, but what you are refering to here is a different type of display - this would actually be called a "LED Dot Matrix Display" or now simplified to "LED Matrix Display".
When i was involved for 4 years writing reports for British Rail and Connex regarding faults on these actual units for Slade Green Depot Engineering Department we refered to them as Dot Matrix Display because that is what they are called, it was not a slang name or a reference name it was their technical name for the display unit on a Networkers as fitted from new in 1991/92.
All the best
Karl
My father was the Driver Standards Manager at the time, so guess how i got the job 
