If it's serialized then it's really moving along! if you've got 1K
pixels at a
nominally 65 MHz pixel rate with 24 bits per pixel ... I assume the
designers at
least use three channels, one for each color, so as to reduce that
to 8 bits per
pixel, right?
Use lossless compression, then even hires displays rarely get over 20Mb/s
For most applications, the distance from the "box" to the display
isn't far at
all, but I can see the benefit where a large display might be
desirable, as in a
classroom or demonstration environment.
Or multi drop.
Nevertheless, aside from relatively small signal losses, there isn't
a big
advantage, aside from the fact that every display manufacturer can
process the
signal however he prefers.
Cheaper connectors, cheaper cable, no mismatch artifacts...
What sort of connector is used for the serialized digital
arrangement?
BNC mostly.
Lee.
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"Russ Blakeman" <rhblake(a)bigfoot.com> wrote:
> Much like the term "collectable" - what wide open term. Hell anything is
> collectable since you can collect it, even trash. The local dump has all
_Everything In Entire World Now Collectible_
http://www.theonion.com/onion3710/everything_collectible.html
"According to a report issued Monday by the North American Collector's
Association, every single thing currently being manufactured is officially
categorized as a collectible."
-Frank McConnell
Not only that going from TTL to analog you will over dirve in the
input amps and likely get ringing or saturation effects. All look bad.
Allison
-----Original Message-----
From: Richard Erlacher <edick(a)idcomm.com>
To: classiccmp(a)classiccmp.org <classiccmp(a)classiccmp.org>
Date: Friday, May 11, 2001 9:26 PM
Subject: Re: Converting TTL monitor to Analog
>Well, I'm not sure you're entirely wrong here, but the ghosting is
probably more
>a result of poor signal termination than anything else, and the
magnitude of the
>reflection from a full-swing digital signal is much more likely to show
up than
>what you'd get form a 1-volt p-p analog signal. Moreover, since you've
got much
>smaller transitions on the analog video signal, and since you've got an
>automatic gain control in the monitor to offset the losses, the line
losses
>aren't as much a factor as they'd be without it. Digital signaling was
OK back
>in the text-only and monochrome era, but once things went to
full-spectrum
>color, it was necessary to present them in analog. The EGA had 16 (?)
colors
>(maybe that was 16 shades of each of three colors), which already
required some
>digital=>analog processing at some stage in the process, and, from what
I've
>observed, it had to be on the adapter board, since the signal from there
to the
>monitor was already a small-swing analog signal.
>
>Gosting is another problem that's never plagued me in this arena.
Normally it
>can be dealt with by proper termination of the video signal. Some
monitors rely
>on a 150-ohm resistor in the line and only provide that same amount
themselves,
>while other have a 75-ohm to ground/return. To accompany this some
adapters
>have a divider rather than simply a series resistor to the output. It
depends
>on what's in the combination, how well it will work, but I've not been
>sufficiently bothered by any mismatch to warrant hacking either circuit.
>
>Dick
>
>----- Original Message -----
>From: "Iggy Drougge" <optimus(a)canit.se>
>To: "Richard Erlacher" <classiccmp(a)classiccmp.org>
>Sent: Thursday, May 10, 2001 5:26 PM
>Subject: Re: Converting TTL monitor to Analog
>
>
>> Richard Erlacher skrev:
>>
>> >What sort of digital interface would such devices use? They'd have
to have
>> >lots of wires, e.g. 26 or so pairs, if the thing is using 24-bit
color.
>> >Perish the thought someone would use more color depth than that!
It's hard
>> >to imagine they'd do that. The number of wires that have to
transport
>> >high-frequency signal is the reason the analog is still so difficult
to
>> >surpass.
>>
>> >After all, a 26-pair shielded cable with an appropriate connector,
made in
>> >the US, would immediately become the most costly component in a
computer
>> >system. I doubt a computer maker would go for that, as the 20"
monitor
>> >(@~$300-$400) is presently the most costly component. That would
essentially
>> >make the 20" display and cable more than 2/3 the cost of the
computer.
>>
>> But isn't the digital signal less dependent on absolute signal
integrity?
>> After all, if there can only be two levels, making out the difference
can't be
>> all that difficult. This also seems to hold true WRT my successful use
of
>> long, thin, unshielded cables for EGA and CGA monitors without any
ghosting.
>>
>> --
>> En ligne avec Thor 2.6a.
>>
>> I dunno, I dream in Perl sometimes...
>> --Larry Wall in <8538(a)jpl-devvax.JPL.NASA.GOV>
>>
>>
>
If your systems have a DL(V)11E/f your set with the right cable.
That means a PDP-11 (Q or U) or Qbus Vaxen (maybe a U bus).
Allison
-----Original Message-----
From: Megan <mbg(a)world.std.com>
To: classiccmp(a)classiccmp.org <classiccmp(a)classiccmp.org>
Date: Friday, May 11, 2001 9:38 PM
Subject: Re: In search of 20ma to eia converter
>
>>Which PTR do you have thats 20ma?
>
>I don't have it in front of me right now, but I think it is the PRS01,
>a small reader (6x12x8) which is a table-top unit.
>
> Megan Gentry
> Former RT-11 Developer
>
>+--------------------------------+-------------------------------------+
>| Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com |
>| Unix Support Engineering Group | (home): mbg!world.std.com |
>| Compaq Computer Corporation | addresses need '@' in place of '!' |
>| 110 Spitbrook Rd. ZK03-2/T43 | URL: http://world.std.com/~mbg/ |
>| Nashua, NH 03062 | "pdp-11 programmer - some assembler |
>| (603) 884 1055 | required." - mbg KB1FCA |
>+--------------------------------+-------------------------------------+
SOmebody said they were looking for one of these,
please contact me off-list.
Thanks
Jeff
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Hello, all:
I have an old CGA monitor that's working now, but I can envision it
someday soon not working. So, I was wondering if anyone has built a
converter so that they can use a standard VGA monitor (analog) on a CGA
output (TTL)?
Rich
The VAXstation 3500 has been claimed.
--
Brad Ackerman N1MNB "[John Howard] hasn't emerged from the 1950s,
bsa3(a)cornell.edu and he seems rather resentful of anyone who has."
http://skaro.pair.com/ -- Bill Leek, _Australia: Beyond the Fatal Shore_
>Which PTR do you have thats 20ma?
I don't have it in front of me right now, but I think it is the PRS01,
a small reader (6x12x8) which is a table-top unit.
Megan Gentry
Former RT-11 Developer
+--------------------------------+-------------------------------------+
| Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com |
| Unix Support Engineering Group | (home): mbg!world.std.com |
| Compaq Computer Corporation | addresses need '@' in place of '!' |
| 110 Spitbrook Rd. ZK03-2/T43 | URL: http://world.std.com/~mbg/ |
| Nashua, NH 03062 | "pdp-11 programmer - some assembler |
| (603) 884 1055 | required." - mbg KB1FCA |
+--------------------------------+-------------------------------------+
Sigh, I've been going through my stuff, paring it down 'cuz I have to move
it :-), and this has given me incentive to actually go through some of the
systems I've bought but had 'staged' for later analysis. One is a MicroVAX
3600 in the H9644 cabinet. This is a pretty big VAX for the Q-bus series.
I've seen custom configs done bigger with the BA23's in a tall corporate
rack but as a unit, this was one of the larger Q-bus VAXen around.
Now normally these things had the BA213 mounted in the lower part of the
rack and a big RA81 or RA82 mounted in the top. One of the things that
excited me about this machine was that the RA82 has been removed and
replaced with a case filled with 4 SCSI drives and an 8MM DAT drive. SCSI
drives normally imply a SCSI interface, but alas, I opened it up and there
is one open slot in the backplane and no bus grant jumper. I can guess what
used to be there. Oh well.
However, one of the other things was an Emulex board that I'm trying to
identify. It has these numbers:
K12S12/500W
SN: AAG6933 CM
Assy #: QS0910201-02
Then four high density 36 pin honda connectors on an Sbox handle. There is
also a small three position switch labeled 'norm', 'reset', and 'setup.'
I'm guessing it is some sort of async port. Anyone know for sure? Does
anyone know the actual Emulex model number and if cables are available? If
its a 32 port serial card it would be pretty cool.
--Chuck
Available immediately, a VAXstation 3500 with:
TQK70 tape controller
KDA50 SDI adapter
VCD02 frame buffer (4-plane)
DSV11 2-line sync SLU
DESQA Ethernet adapter, thick/thin
MS650 8MB memory board (x2)
KA650 CPU board (MicroVAX III)
plus a VR290-DA colour monitor (some ghosting), LK-401 keyboard, VSXXX-AA
mouse, the keyboard/mouse breakout box, and the power cable. Storage
devices installed are a TK70 (control panel indicates a fault of some
sort; all three LEDs on the drive blink) and an SID hard drive (c. 270
MB[1]). Also appears to need a new clock battery. Free to a good home;
currently located in Somerville, Massachusetts, USA near I-93 exit 30.
[1] If I'm reading the output of SHOW DEVICE DUA0: /FULL correctly.
--
Brad Ackerman N1MNB "Now some of you may bring up the Tekken OVA.
bsa3(a)cornell.edu In response, I'd tend to simply bring up my lunch."
PGP: 0x62D6B223 -- His Lordship Chaos
http://skaro.pair.com/ from http://www.animeondvd.com/
