was port addressed using the TI colour video controller. This controller
features ‘sprites’, which are preformed patterns which can be manipulated with
incredible speed once set up. I have yet to see one of these cards working,
but I have heard dark mutterings from various directions about the damn thing
not doing what was expected of it.
Some time ago a sample card was shipped down from Edinburgh University
for a group of dealers to offer their opinions. Very few details were supplied
with it, except that it was a port addressed 8" x 8" card, the resolution was
something like 350 x 256, but its most interesting feature was that the demo
displayed amongst other things a test card with a 16 step grey scale wedge.
Some time during the day the card (which was after all a prototype) crashed
and at the end of the day it was shipped back to Edinburgh. That is the last
that has been heard of it – a pity, a could be a contender in the colour card
As I said earlier, I can not recall anything about the A N Other card
which was discussed at the East Grinstead meet.
I have also seen the circuits and chat about a Dutch designed colour
card which was published in the Dutch equivalent of ‘Nascom News’. This one is
similar to the Climax card except it uses the 256 x 512 version of the video
controller and has an AY-3-8910 sound chip on it as well.
THE COMPARATIVE REVIEW.
Of those listed above only three are in serious production, the Pluto,
the Nascom and the Climax. I have been having fun (or tearing what’s left of
my hair out) with these. I propose to review the features of each of the cards
under different subheadings. Where appropriate I shall digress.
For the first digression, and before getting on with the review, let’s
have a have a look at the display requirements. Colour monitors are not cheap,
and the domestic colour TV appears at first sight to a be viable alternative.
Unfortunately, the easiest entry into the domestic TV is the RF input, which
just happens to be the most unsatisfactory. Some TV’s notably of European
origin, Normende, Grundig, etc, have composite PAL inputs on the back for
connecting Video Cassette recorders, which would be satisfactory with the
Climax card. Many TV’s have RGB inputs for the inclusion of Teletext panels if
you know where to look, but it is highly dangerous to assume that these would
make a safe connection as most colour TV’s use chassis live to one side of the
mains, and connection here is a quick way of taking a ride to the mortuary. So
unless the TV has the right connections on the back, or unless you are
thoroughly aware of what you are about, DO NOT make connections inside the
domestic TV set.
The Nascom and Pluto cards do not have RF outputs on the grounds that
the resolution is too high for the domestic TV, certainly true in the case of
the Pluto, perahps arguable in the case of the Nascom. The Climax card is
fitted with a modulator for connection into a TV. Even so, the results from a
TV are very much inferior to the results from even a modest colour monitor.
So to the choice of monitors. These are normally available in three
resolutions and with two types of input, analogue and logic. Resolution first.
Not all manufacturers make all types, but the information can usually be
extracted from the data sheets, albeit, sometimes disguised as something else.
Resolution is usually measured in vertical lines. Not to be confused with the
number of horizontal lines on the display. Vertical line resolution is taken
as the maximum total number of vertical black/white lines the display is
capable of resolving across its face, and is a function of the fineness of the