Product Review (November 2003) - Gefen
DVI 1000HD DVI Extender System

DVI has become the interface of choice for today's videophiles and home theater enthusiasts. Many higher end video products now come standard with this digital interface, which increases the demand for DVI cables. While plasmas and RPTVs usually don't run into cable length issues, ceiling mounted projectors located far from the main video source often need cables longer than those currently available. Sending this very high-speed data requires a robust interface and increasing the cable length usually results in degraded signal integrity. Due to the encoding process that serializes the RGB video, a single DVI link requires data rates around ten times the actual pixel rate. The DVI interface uses four TMDS (Transition Minimized Differential Signaling) channels developed by the folks at Silicon Image with serial data rates often exceeding 1 GHz (one billion bits per second) as resolutions and scan rates increase. For this reason manufacturers are reluctant to produce long DVI cables that would inevitably reduce the noise margin to a point where data may become unreliable. Sending digital data to the display or projector using DVI has some significant advantages over standard analog RGB or YPrPb cables. Long cable runs increase capacitance and usually result in some loss of high frequency detail giving the picture a softer look. In addition, slight impedance mismatches in the cable can result in ringing and other anomalies that are objectionable on large screen displays.

Gefen Incorporated, a manufacturer of DVI products, appears to have solved this problem by converting electrical data into high-speed fiber optic data. The design uses two dual mode LC fiber optic cables for a total of four fibers. This allows each of the four TMDS channels defined in the DVI specification to have its own fiber optic link. Using the DVI 1000HDS and DVI 1000HDR units, data can be transmitted and received over very long distances without the concern of signal degradation. The DVI 1000 is designed to work with data rates as high as 1920x1200. The design supports the DDWG (Digital Display Working Group) specification for DVI compliant monitors. The chassis design for the sender and receiver are identical in size, measuring only 3.25" D x 4.25" W x 1" H.

Fibers
The four fiber optic cables used in the system are bundled into a single jacket, making it easier to handle and less likely to damage. However, I would caution those who use this system to take special care not to kink or stress the cable in any way. Doing so may indeed break a fiber and render the system useless until the fiber is replaced. I'm currently working on a project where we use fiber optic cables and we have broken them in some instances, so I tend to lean towards the cautious side. Rubber plugs are placed into the optical jacks located on the sender and receiver units to prevent contamination from entering the openings. Likewise, caps are installed on the fiber cable ends to keep them clean.

The DVI 1000HD system is designed to run distances as long as 500 meters or 1640 feet. That's well over a 1/4 mile in length. The interface also requires a CAT5 cable the same length as the fiber cables, but runs at a much slower data rate. The CAT5 is used to send HDCP/DDC and control signals. Yes, this system is fully HDCP compliant, so you can rest assured that encrypted data will make it to your display. This is especially important as we move into an era of strict content protection from studios and broadcasters.

Installation
Installation is very simple with the fiber optic and CAT5 cable connectors clicking into place on each of the units. The most difficult task is routing the cables in the walls and through the ceiling. Both the transmitter and receiver have DVI and power connectors. We connected the supplied 6-foot DVI cable to our Marantz VP-12S2 projector and Gefen receiver unit. We used an Accell Corporation Gold Series DVI cable between the Mitsubishi HD-5000 set-top receiver
and the Gefen transmitter unit. Powering the DVI 1000HD requires that only one of the two units be plugged into the power adapter. The user can choose whatever side is more convenient to power without any difference in video performance. The unpowered unit gets its power from the CAT5 interface cable. We installed the power adapter on the transmitter since we had sufficient room near our Marantz VP-12S2 projector. Once the link is made and power is applied to the system, the Power and Status indicators on the front of the units let you know everything is working correctly.

Performance
We watched several different television programs using the new Mitsubishi HD-5000 set-top receiver with a Marantz VP-12S2 projector and Mitsubishi PD-5010 plasma display. Here in Los Angeles, the Tonight Show offers an excellent picture and was one of the first high-definition programs to air in the area. The DVI1000HD system worked very well and produced an excellent picture over the 100 feet of cable with no problem at all. We also watched an episode of Law & Order: Special Victims Unit on KNBC and the picture was equally impressive. This setup appeared to be working flawlessly in our setup with absolutely no dropouts or anomalies that would degrade the video performance. As a comparison, we swapped out the DVI 1000HD system with a 30-foot Transparent High Performance DVI cable and saw no difference in video quality between the two setups. The Transparent cable we used in the comparison retails for about $1000 and has excellent performance. The cost for the Gefen DVI 1000HD system with 100 feet of fiber optic cable costs $1,378 (as tested) and performed equally as well with our DVI/HDCP products. The obvious advantage of the Gefen DVI 1000HD is that it can run very long distances while maintaining DVI signal integrity.

Conclusion
Videophiles typically choose specific cables for specific video applications. The high bandwidth requirements of HDTV and especially DVI, forces consumers to pay more attention to this issue. As a result, spending more money on quality cables can be rationalized to many consumers building their home theater system. DVI interfaces have certainly become more common and the vast majority of us can get away with short simple cables for our display. However, if distance becomes a barrier for large theater rooms, Gefen's DVI 1000HD system offers a real solution without the worry of degrading the picture over the long cables runs. Since HDCP equipment is also becoming a reality, this must be addressed and fortunately the DVI 1000HD is fully compliant. I'm currently not aware of any other company making this type of system for the home theater market. While the cost of the interface may seem high, just compare it to any of the long cables being offered by the high-end manufacturers. Few companies are capable of producing long cables that work reliably (50+ feet) and none have lengths (1/4+ mile) that even come close to the Gefen DVI 1000HD system.

- Kevin Nakano


Review System

Projector: Marantz VP-12S2 High-Definition DLP™
Screen:
Stewart Filmscreen 100" Luxus Deluxe FireHawk Screenwall
Display:Mitsubishi - PD-5010 50" High-Definition Plasma Display
Preamplifier/Processor: Parasound AVC-2500U THX-Ultra DTS/DD Preamp/Processor
Amplification: Parasound HCA-2205AT THX-Ultra Five Channel Amplifier
Bass Management: Miller & Kreisel BMC Mini 5.1 Bass Management Controller
Front Speakers: Miller & Kreisel S-150THX (L+R) and S-150AC (Center) Speakers
Rear Speakers: Miller & Kreisel SS-250 TripoleŽ Surround Speakers
Subwoofer: Two Miller & Kreisel MX-350THX MkII THX-Ultra Push-pull Subwoofers
Room Treatments: Echo Buster panels and Bass Buster towers
Set-top Box: Mitsubishi HD-5000 Receiver
D-VHS VCR #1: JVC HM-DH30000U D-VHS High-Definition D-Theater VCR
D-VHS VCR #2: Mitsubishi HS-HD2000U D-VHS High-Definition VCR
DVD/CD/SACD Player: Sony DVP-NS900V DVD/CD/SACD Player
DVD Audio/Video Player: Kenwood Sovereign DV-5900M 400-Disc DVD Changer
Laserdisc Player: Pioneer CLD-D704 CD/VCD/LD Player
A/V Cables: Ultralink Platinum and Advanced Performance Series Cables
DVI Cable #1: Monster Cable M Series M500DVI DVI-D Cable
DVI Cable #2: Accell Corporation Gold Series DVI-D Cable
Video Generator: Sencore VP300 SDTV/HDTV Video Pattern Generator
Video Signal Analyzer: Sencore VSA794 NTSC Video Signal Analyzer
Color Analyzer: Sencore CP5000 Multi-Display Color Analyzer


Review - At a Glance

Gefen - DVI 1000HD DVI Interface Extender Kit

Features:

  • Two dual mode LC fiber optic cables (4 total)
  • CAT-5 cable for DDC and control signals
  • Extends any DVI compliant device up to 1640‘ (500 meters) from the source
  • HDCP Compliant
  • Supports 480p,720p,and 1080i video signals
  • Up to 1920 x 1200 resolution
  • Supports DDWG standard for DVI compliant monitors
  • Easy Installation

    Specifications:
    Video Amplifier Bandwidth:

    1.65 GHz

    Input Video Signal: 1.2 volts p-p
    Input DDC Signal: 5 volts p-p (TTL)
    DVI Connector Type: DVI-D
    Link Connector: RJ-45
    Power Consumption: 15 Watts (max)
    Dimensions: 3.25”D x 4.25 ”W x 1”H (Transmitter and Receiver)
    Shipping Weight: 3 lbs.

    Kit Configurations:
    All kits include DVI 1000HD, Fiber Optic and CAT5 Cables
    Kit #1 (60 foot)

    $1,299

    Kit #2 (100 foot): $1,378
    Kit #3 (150 foot): $1,518
    Kit #4 (300 foot): $1,668

    Includes:

  • DVI•1000HDS (Sender)
  • DVI•1000HDR (Receiver)
  • One 12v Power Supply
  • One 6ft DVI cable (M-M)

  • Company Information
    Gefen Inc.
    Customer Service
    6265 Variel Ave.
    Woodland Hills, CA 91367-9897
    Toll Free: 800-545-6900
    Phone: 818-884-6294
    Fax: 818-884-3108

    Source: Manufacture loan
    Model Number: DVI•1000HD (Kit #2)
    MSRP: $1,378 (as tested)

    Warranty: 1 year parts and labor

    URL: www.gefen.com

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