HDMI products have become the interface of choice for all high definition equipment. Many of the earlier displays and even some current ones, including projectors, only offer a single HDMI input. As a result, HDMI video switchers emerged to allow user to easily switch between HDMI-capable components. Atlona Technologies, a subdivision of Lenexpo Electronics, has created the AT-HDMI41, a new 4-to-1 HDMI video switcher designed to switch between four HDMI sources. The AT-HDMI41 includes an IR remote and provides an RS232 interface that allows an external controller to command the unit. The construction of the AT-HDMI41 is solid with a fully metal chassis that measures a moderate 9.5" W x 4.25" D x 2" H in size.

Front Panel
The front panel of the AT-HDMI41 has six LEDs and two buttons. The Input button cycles through each of the HDMI inputs with the corresponding LED indicating the active channel. TheSignal Enhance button on the right side with the yellow LED indicator provides additional amplification to boost the HDMI signal in the event longer cables are used with the switcher. This is a common problem with many of the longer passive cables available today.

Rear Panel
The rear panel of the AT-HDMI41 has the four HDMI input connectors and the single HDMI output connector. The RS232 interface and power jack are also found here. Powered by an external universal (100-240VAC, 50/60Hz) high-efficiency switching AC power adapter, the AT-HDMI41 is supplied with 5V at up to 2.6A. The 9-pin RS232 connector allows the unit to be controlled from an external unit such as a PC or high-end controller.

Design
The AT-HDMI41 uses a trio of Texas Instruments TMDS341A switching devices cascaded into two levels to handle the four HDMI inputs. This approach works well and the performance of the devices is excellent in this unit. Control of the switches and the RS232 interface is handled by a onboard SyncMOS SM8952A processor with external EEPROM for nonvolatile storage. We found that even if power is removed from the unit, the last configuration state is saved and will be restored when the unit is powered on again. Many products will simply go back to a default setup when power is interrupted. This was an impressive feature that we found by accident.

Performance
We had three HDMI sources routed through the AT-HDMI41 switch for testing. Our Dish Network ViP622 HD receiver, Toshiba HD-A1 HD-DVD player, and an OPPO Digital OPDV971H DVD player all fed the inputs of the switch. The video output from the AT-HDMI41 switch went through a long 25-meter Atlona (AT14030-25) active HDMI cable, eventually making it to our Mitsubishi HC5000 projector. This cable is an astonishing 82-feet long and delivered error-free video to our projector. We had a variety of high definition content from both the ViP622 and HD-DVD player and scaled up (1080i) video from the OPPO OPDV971H DVD player. Video looked fantastic with excellent resolution from our high definition sources. All video was in the form of 1080i, so we didn't push the switch to the 1080p barrier. However, we did try the same Atlona (AT14030-25) active HDMI cable directly from our Sony PlayStation3 to the HC5000 projector and the video looked stunning in 1080p.

Remote Programming
The AT-HDMI41 comes with an IR remote (CR-22) to select the input channel and to power the unit on and off. This small remote looks similar to the ones supplied with typical camcorders. Unfortunately, they do not appeal to me because they are small and not agronomic. Fortunately, most universal remotes can be programmed with the needed IR commands without a problem.

If the user has a more sophisticated setup in their viewing room, the rear RS232 interface can be used to control the unit. However, we could not find any documentation that describes the serial interface such as baud rate, data size, stop bits, etc. Thankfully, after inquiring we obtained a document that contained the needed information (here). In our case, we have an RTI T4 controller that can store virtually any IR remote code or send serial commands through a wired interface. Either way, documentation is needed for this.

Conclusion
The Atlona AT-HDMI41 is a high performance HDMI switcher capable of solving the problem of limited HDMI inputs. The performance we experienced with this switcher gave us confidence that Atlona is capable of being part of our reference system and meeting the demands of video enthusiasts. Furthermore, the retail price ($249) of the AT-HDMI41 is very reasonable, making it highly competitive. The included IR remote and RS232 interface gives the user options on how to integrate the switch into their system.

- Kevin Nakano

Projector: Mitsubishi HC5000 Full 1080p High-Definition LCD Projector
Screen: Stewart Filmscreen 100" FireHawk Screen on a Luxus Deluxe ScreenWall
Video Processor/Scaler: Anchor Bay Technologies DVDO iScan HD+ A/V Processor
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 Tripole® 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: Dish Network ViP622 HDTV Satellite and Terrestrial Receiver with HDMI
Blu-ray DVD Player: Sony PlayStation3 with HDMI
HD-DVD Player: Toshiba HD-A1 HD-DVD Player with HDMI
DVD/CD/SACD Player: Sony DVP-NS900V DVD/CD/SACD Player
DVD Audio/Video Player: Kenwood Sovereign DV-5900M 400-Disc DVD Changer
DVD Player: OPPO Digital OPDV971H DVD Player with DVI Output
D-VHS VCR: JVC HM-DH30000U D-VHS High-Definition D-Theater VCR
Media Server: Kenwood Sovereign MRH1 Entre
Remote Control: Remote Technologies Inc. T3 Controller
HDMI Cable: VizionWare Hi-Wirez 15-meter Active 1080p Cable
HDMI Cable: Accell UltraRun 45-meter 1080p Cable
DVI Cable: AudioQuest DV-1 20m DVI-D Cable
A/V Cables: Ultralink Platinum and Advanced Performance Series Cables

• Supports high resolution input: up to 1080p.
• HDCP Compliant
• HDMI 1.2, HDCP 1.1 and DVI 1.0 compliant.
• The unit has the function of Signal Enhancer to improve signal quality after long distance transmission.
• Ideal for home theater integration.
• IR Remote control.
• RS232 input for connecting to control system
• Easy to install and simple to operate.

Any comments or questions regarding the LAAF Web Site should be forwarded to webmaster@laaudiofile.com

Copyright © 1985-2007 L.A. Audio File.