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Author Topic: NEC PA241W and PA271W display port cable  (Read 19894 times)

Roy

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NEC PA241W and PA271W display port cable
« on: October 07, 2010, 11:29:57 pm »

OK, a bit off topic for the colour management forum, but this is where the NEC PA2x1W users seem to be.

The NEC monitor ships with a full size display port to full size display port cable which isn't much help to owners of newer Macs which use a mini display port video connector. Arrogant Apple (at least here in Canada) does not sell a mini display port to full size display port adapter, and if it did, it would cost $35. However, your local PC computer hardware store can help. StarTech, a widely-distributed maker of PC accessories, makes a nice cable with mini display port on one end and full size display port on the other. The three foot cable is product MDP2DPMM3 and it works perfectly with a MacBook Pro. I had to order it as it was not a stock item, but it cost only $7 Cdn.
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julianv

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Re: NEC PA241W and PA271W display port cable
« Reply #1 on: October 08, 2010, 04:11:14 am »

Monoprice.com has Mini DisplayPort to DisplayPort cables, and an adapter that converts from male DisplayPort to male Mini DisplayPort.  Very low prices.  I would include direct links to the product pages, but their website is down for maintenance right now.

However, you should be aware that NEC is alerting customers to problems with some of the cables currently on the market.  I don't know if the ones from Monoprice are included in their warning.  Read their notice here.




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K.C.

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Re: NEC PA241W and PA271W display port cable
« Reply #2 on: October 23, 2010, 11:49:57 pm »

Arrogant Apple (at least here in Canada) does not sell a mini display port to full size display port adapter, and if it did, it would cost $35.

I don't sell anything I can't make money on either. That's not arrogant, it's good business.

As you and the other poster have noted, adapters are readily available.
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Roy

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Re: NEC PA241W and PA271W display port cable
« Reply #3 on: October 24, 2010, 08:34:22 pm »

As you and the other poster have noted, adapters are readily available.

Turns out, the "other poster" (me) was wrong. Adapters are not readily available. Most, including the adapter cable I purchased, have the flaw noted in the NEC document that julianv referenced. I didn't notice at first.

The trick is to use the cable supplied by NEC and put a female display port to male mini display port adapter on the computer end of it. The NEC cable does not connect power between devices (which is the problem discussed in the NEC document); it doesn't matter if the adapter you purchase passes power so long as you use it to adapt the NEC cable (not replace it) because the NEC cable breaks the power connection.

As an alternative, you can use a short male mini display port to male display port cable with the computer and link it to the NEC cable with a female to female display port connector. This has an advantage on a Mac notebook as the ports are very close together and there isn't room to use a male mini display port to female display port adapter if you wish to use the adjacent ports. The m-m cable plus f-f connector solve this problem. However, keep the mini display port to display port cable to no more than one metre in length if you are running the 27" display at full resolution as there is a three metre total cable length limit in the display port spec at full bandwidth and the NEC cable is two metres. This is the solution I ended up with and it works fine: computer can sleep, no power up problems with the computer, no power up problems with the display, running the display using both a Mac Pro on DVI and a MacBook on display port works.
« Last Edit: October 24, 2010, 08:41:49 pm by Roy »
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Mark D Segal

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Re: NEC PA241W and PA271W display port cable
« Reply #4 on: October 26, 2010, 11:28:34 am »

What works on a MacBook Pro does not necessarily work on a MacPro, and don't ask me why. I have a Kanex mini-to- full DisplayPort cable (6 foot) sold by an Apple reseller here in Toronto which illuminates my NEC PA271W from my mid-2010 MacBook Pro, but will not illuminate the same display when connected to the MacPro, also mid-2010 Westemere model. The REAL SIMPLE solution to this problem for the time being is - on the MacPro - to avoid using the mini-DisplayPort altogether and connect the display using a DVI to DVI cable from the DVI port on the video card. We dol not get 10-bit pixel depth from this, but Mac OSX Snow Leopard doesn't support it anyhow. I have brought this problem forcefully to the attention of both Apple and NEC. NEC have been substantively responsive, and they are now testing a number of cables and adapters at their labs in Japan. I understand that there will be more news from NEC on this matter perhaps within several weeks. It will take a while until the engineers finish their tests and analyses, propose the solutions and these are then subjected to quality control procedures before being issued. According to what is known at the moment, the main problem is that power should not pass through the 20th pin and most of the cables on the market don't respect this specification. There are deeper and broader implications about this whole sad saga of mini-DisplayPort relating to how industry works or doesn't work, but at least from me those will await another day. The first priority is to nudge them into solution mode and that is happening. As I said, NEC is being substantively helpful, notwithstanding that mini-DisplayPort is a technology imposed on us by Apple Computer. It's a neat way of keeping laptops thin, but it stops there.
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Mark D Segal (formerly MarkDS)
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Roy

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Re: NEC PA241W and PA271W display port cable
« Reply #5 on: October 26, 2010, 12:26:42 pm »

Mark,

If you wish to connect your Mac Pro to your NEC display, buy an adapter like this and use the NEC display port to display port cable that came with the monitor (NOT a third party cable). Startech is well distributed in Canada, you should be able to order the adapter from any shop that sells PC computer parts (but perhaps not at an Apple dealer), and others make similar male mini display port to female full size display port adapters.

As I mentioned in the post above, this type of adapter may obstruct other ports on a MacBook and I suggested another way to make a connection to a MacBook. I suspect that if you dig a bit further you will find that the cable you presently own does not work properly with your MacBook Pro. I have a similar cable and it gave a good image on the display, but there were power on/off problems with the display and sleep problems with the MacBook when using the cable. Adapting the NEC-provided full size display port cable to the MacBook Pro resolved all problems.

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Roy

Mark D Segal

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Re: NEC PA241W and PA271W display port cable
« Reply #6 on: October 26, 2010, 12:52:19 pm »

Roy, I'm well aware of all that. The bottom line is that these companies MUST take ownership of the problems they create and offer solutions which they WARRANTY. Once either Apple or NEC, and it will be most likely the latter, confirm a solution, and they stand behind it, I shall implement it. If I use one of these gadgets on my particular configuration and it screws something up, with no hard-feelings intended, the people on web forums who in good faith recommend these things are not positioned and not supposed to be compensating me for any damage. Yes, I may be cautious to a fault about these things, but there's simply too much time and money involved for me to be comfortable otherwise.
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Mark D Segal (formerly MarkDS)
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julianv

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Re: NEC PA241W and PA271W display port cable
« Reply #7 on: October 26, 2010, 06:46:18 pm »

I am running a PA217W, MacPro1,1 (2006, first generation), ATI Radeon HD 5770, connected by the NEC-provided DisplayPort to DisplayPort cable, and the adapter from Monoprice, linked here.

I am seeing two problems with this system.  I am not getting 10-bit per color channel output, as advertised by NEC.  It looks like this problem may be in the video card driver.  NEC, AMD and Adobe are denying any responsibility, and some of the fingers are pointing at Apple, since they develop and distribute the driver as a component of OS X.  See this thread on the Adobe forums for more info (what little info there is).

The other problem is that my display occasionally fails to light up when the Mac wakes up from sleep.  Power cycling the monitor or reinserting the display cable fixes this, but it is still a minor annoyance.  I don't know whether this is also a driver bug, or an issue with the cable and/or adapter.  I noticed that the Startech adapter is priced much higher than the one from Monoprice that I am using - is there a difference?  I am curious to know if anyone else is seeing the wake-from-sleep failures with the Monoprice part.
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Roy

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Re: NEC PA241W and PA271W display port cable
« Reply #8 on: October 26, 2010, 07:24:36 pm »

julianv, The adapters are passive devices, no electronics inside, they just contain wires to connect the 20 pins on the mini display port connector to the 20 pins on the full size display port connector. It is very unlikely that there are any differences between brands.

As for 10-bit data, I wasn't aware that Apple supported 10-bit data.
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Mark D Segal

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Re: NEC PA241W and PA271W display port cable
« Reply #9 on: October 26, 2010, 08:35:28 pm »

To further clarify the nature of this issue, in case I was not explicit enough above, there are two problems: (1) whether a cable or adapter which converts from Apple's mini-DisplayPort to the rest of the world's regular DisplayPort is capable of illuminating the display, and (2) if it is, at what pixel depth (8 bit or 10 bit) is the display operating. Problem (1) is a cabling issue which should never have have happened if the concerned companies had ensured from the get-go that certified, workable cables with one mini-DisplayPort terminal would be available either from them or supported by them from the day the equipment hit the market. They didn't do it, now they are being forced to do it because customers are howling at them, and NEC has informed me that they are making progress on the matter (but no substantive commitment from Apple Computer on any of this, despite the fact that they are the ones forcing mini-DisplayPort on us). As I said above, NEC has told me that the problem stems from whether power is being passed through the 20th pin. Cables and adapters need to leave the 20th pin open, otherwise the display will simply not operate or operate erratically. Manufacturers of cables and adapters need to respect this condition. (On the importance of the reliability of adapters, I have observed that even one you can buy from the Apple store for converting from mini-DisplayPort to DVI appears to be of questionable operational stability; and I am not alone in this observation. So the quality and reliability of adapters is a live issue.) Turning to problem (2) - the issue of pixel bit depth, which determines how many millions of colours the monitor can display, firstly, one needs DisplayPort connection technology to deliver 10 bit depth, and secondly, the computer's operating system must support it. The PA series displays from NEC are advertised to be fully capable of delivering 10-bit per pixel depth, but it is not being delivered because Snow Leopard does not support it. Both NEC and Apple Computer have confirmed this to me. There is nothing NEC can do about that because they are not responsible for the computer's operating system, and Apple Computer will not commit themselves to tell me what they intend to do about it, even though I just paid them a large sum of money for their flagship MacPro. So that's the status of this problem now: we have technological inadequacy related to how mini-DisplayPort can communicate with any other type of connection, and we have an operating system limitation frustrating customers' intentions to have the vastly more refined palette of colours which these NEC models are capable of delivering. This by the way does not affect the size of the available colour space - bit it does affect the finesse of the tonal gradations within it, and one of the reasons why we paid the big bucks to own it. It is of course outrageous that customers for these expensive systems should have to fish around the market place taking technical risks to solve operational problems caused by inadequate due diligence on the part of key players in the industry. 
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Mark D Segal (formerly MarkDS)
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Roy

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Re: NEC PA241W and PA271W display port cable
« Reply #10 on: October 26, 2010, 10:54:13 pm »

Mark, to clarify your clarification, some adapters such as the mini display to dual-link DVI adapter are active. The mini display port to display port adapter is passive; just two connectors, some wire and a shell. Like selecting an extension cord for a table lamp, buy the cheapest that has decent mechanical quality.

Enough of this.
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Roy

Mark D Segal

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Re: NEC PA241W and PA271W display port cable
« Reply #11 on: October 26, 2010, 11:31:56 pm »

"Enough of this" perhaps if you can explain why Julian is getting the strange behaviour he reports using the Monoprice adapter. Maybe the adapter is a piece of junk? NEC is testing it in Japan and they won't pass on it till their quality control people confirm it is satisfactory. Whether it is active or passive is kind of irrelevant to the fundamentals of the problems being discussed in this thread.
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Mark D Segal (formerly MarkDS)
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Roy

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Re: NEC PA241W and PA271W display port cable
« Reply #12 on: October 26, 2010, 11:58:51 pm »

Perhaps an analogy will help. Buy a new TV and an extension cord because there isn't a nearby power outlet. Bring it home and hook it up to your satellite box. Lousy picture. Focus on the extension cord as the source of the problem.

I can think of many reasons why Julian's monitor fails to wake up when the computer wakes up, but if he is using the NEC cable, I doubt it is the adapter. Mini display port is a big mess, mostly created by Apple. Julian's video card has a dual-link DVI connector and he should use it. Since Apple won't give you 10-bit data on the display port, you lose nothing and save a lot of grief using DVI.

Problem not solved, but avoided. Let's go shoot some photos.
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Roy

WillH

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Re: NEC PA241W and PA271W display port cable
« Reply #13 on: October 27, 2010, 12:19:29 am »

The other problem is that my display occasionally fails to light up when the Mac wakes up from sleep.  Power cycling the monitor or reinserting the display cable fixes this, but it is still a minor annoyance.  I don't know whether this is also a driver bug, or an issue with the cable and/or adapter.  I noticed that the Startech adapter is priced much higher than the one from Monoprice that I am using - is there a difference?  I am curious to know if anyone else is seeing the wake-from-sleep failures with the Monoprice part.

There are a couple of known causes of wake from sleep problems. One is the DisplayPort cable issue mentioned elsewhere and described in detail in the NEC tech info document, and another is a bug in the Mac OS video drivers. The latter is expected to be fixed in an OS update at some point in the future.

For now the safest bet regarding cabling is to use the NEC supplied cable with a Mini DisplayPort male to DisplayPort female dongle.
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Will Hollingworth
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WillH

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Re: NEC PA241W and PA271W display port cable
« Reply #14 on: October 27, 2010, 12:53:43 am »

To help to clarify some of the misinformation regarding 10 bit color depth support on DisplayPort:

Here is a simplified explanation of how 10 bit color operates.

1. The display identifies itself as supporting 10 bits to the graphics card if it's hardware supports it.
Note 1: There is no need to enable anything in the display (at least on NEC displays) - it's all automatic.
Note 2: There is no special "10 bit" DisplayPort cable - all of the video is serial data.

2. The graphics card reads this support capability from the display, and if it's hardware and video drivers support 10 bit output, then it can list a "10 bit surface" as being available to applications that use OpenGL.

3. An application that uses OpenGL asks the video system to list the available video modes (including bit depth support etc.). If the application chooses to do so (i.e. has been written to support 10 bits), it can request a 10 bit drawing surface from the video driver.

4. The application can then output 10 bit color data to this video surface.

Only if all of these steps have been satisfied does 10 bit color data actually get passed to the display.

On Windows, 10 bit support has been available in the video drivers for many months now with the right video card hardware from Nvidia or ATI.
[Side note: NEC will be posting a test application to check for the capability of 10 bit support and show 8 bit vs 10 bit comparisons, for those with a 10 bit display (for anyone going to PhotoPlus this week, we will be showing a demo of 8 vs 10 bits).]

On Mac OS things are a lot more immature as far as 10 bit support goes. So far there is no public information on this yet from Apple as far as what OS versions and hardware supports this.

I'll leave it up to the folks at Adobe to comment on if/when 10 bit support will be enabled in Photoshop etc.

So keep in mind that the everything in the pipeline must be able to support 10 bits, and that applications must be modified to use a 10 bit surface and output 10 bit data to it in OpenGL.

Note: 10 bit support has nothing to do with "wide color gamut". It only gives you 4 times as many levels per primary color, so there is less banding. While it is true that the biggest benefit for 10 bits will be on wide color gamut displays (due to non-gray color levels being further apart in colorspace thus increasing banding slightly), support for 10 bits is not related.
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Will Hollingworth
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Mark D Segal

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Re: NEC PA241W and PA271W display port cable
« Reply #15 on: October 27, 2010, 08:35:45 am »

Hi Will,

Apple does have a few things to which they should respond. As well as yourselves, Adobe is also trying to clarify the situation for customers, as you can see from this thread on the Adobe Forum: http://forums.adobe.com/message/3208434?tstart=0. Chris Cox indicates that Photoshop can handle 10-bit pixel depth provided the other factors cooperate. He mentioned in a post dated October 11th that Apple's latest video driver does support 10-bit, but an Apple senior tech rep since then has told me that Snow Leopard does not. So there is a contradiction here between what two knowledgeable people are saying about the state of Apple's support for 10-bit pixel depth on your displays. I know this is not under your control, but it really would be nice and proper for Apple Computer Inc. to issue a formal public statement clarifying the status of 10-bit display support in Snow Leopard and their graphics drivers. That they can do rather quickly, and it would be very helpful, because it would help to either explain or eliminate a causal factor of the 10-bit problem. It will probably take a bit more to rectify the mess with mini-DisplayPort. On that subject, I know that you guys are testing the Monoprice adapter. I wonder whether you are also testing this one: http://ca.startech.com/product/GCMDP2DPMF-Mini-DisplayPort-to-DisplayPort-Adapter-Converter-Male-to-Female. It is about 7 times the price of the Monoprice adapter, so it would be good to know whether it works better for your displays, when connected to an ATI 5870 or 5770 video card on a MacPro - those being the only two options Apple bundles with these new computers.
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Mark D Segal (formerly MarkDS)
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WillH

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Re: NEC PA241W and PA271W display port cable
« Reply #16 on: November 16, 2010, 12:00:23 am »

[Side note: NEC will be posting a test application to check for the capability of 10 bit support and show 8 bit vs 10 bit comparisons, for those with a 10 bit display

For those who are interested in testing their 10 bit capable systems on Windows, we have posted the app for demonstrating and testing 10 bit capability:

http://www.necdisplay.com/SupportCenter/Monitors/Downloads/
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Will Hollingworth
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Brammers

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Re: NEC PA241W and PA271W display port cable
« Reply #17 on: November 16, 2010, 07:32:04 am »

Hi Will,

Thanks for this - works fine on mine.  I see this kind of issue occasionally when editing and it's great to have a solution.

I'd like to ask when you think Windows 7 will be ready for 10bit colour.  At the moment the integration is a bit clunky - aero is disabled for starters, and PS4 & 5 still only half support the feature.  Any idea when this situation might change?

Cheers!
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