Accell’s UltraAV HDMI 4:2 Audio/Video Switch is either a Dr. Jekyll or a Mr. Hyde of a home-theater product. If you intend to use it with a PC, call the company to find out which personality will manifest itself to you. If you'll use it only with consumer-electronics products (e.g., a stand-alone Blu-ray player), don’t worry—you’re golden.
Accell's switch would be a great solution for folks with multiple HDMI sources and multiple HDMI displays--too bad Accell can't guarantee it'll work with your PC.When we integrated the powered switch—which has four HDMI inputs and two HDMI outputs—into our entertainment system, we discovered a bug in its firmware that prevents it from establishing a proper handshake between some PC videocards on one side and display devices on the other. The switch worked fine when the PC was first booted up, but if we switched to another input and switched back to the PC, our two displays (a ViewSonic n4280 HDTV and an Epson PowerLite Cinema 500 projector) went black. The switch wouldn’t work at all when connected to the HDMI output of an HP Pavilion HDX notebook PC.

Accell tells us the bug doesn’t affect every videocard, and that it doesn’t affect consumer-electronics devices at all. Indeed, when we tested the device with a stand-alone DVD player, it worked like a charm. The problem apparently resides with the firmware’s inability to correctly serve an EDID (Extended Display Identification Data) profile to the PC’s videocard. The EDID informs the videocard of the display’s basic capabilities, including the timings that the display will sync to. If the switch fails to pass the EDID to the videocard, as in our experience, you won’t get a picture.

It’s an unfortunate problem for Accell, because the switch is an otherwise excellent value. The $175 device can not only switch between four HDMI inputs, it sends audio and video to both its HDMI outputs (at resolutions up to 1080p) at the same time. An onboard signal booster enables you to send an HDMI signal much further than the 32 feet the HDMI spec supports (Accell claims a maximum cable length of 82 feet). In our scenario, we connected our playback device to the switch using a three-foot cable, and then ran a six foot cable from the switch to a wall-mounted HDMI jack. This jack is connected to a 32-foot in-wall cable. We then used another three-foot cable to connect the projector.

An infrared remote control is included, and the switch has an IR extender jack and a five-foot cable, so you can hide the box away in an equipment closet. But for all the features and excellent performance the switch delivered with consumer-electronics devices, there’s no way we can recommend this device in its present, flawed form.

Accell expects to ship a new version of the switch in September. This will include new firmware that resolves the PC-compatibility issue (the packaging will sport a helpful sticker that reads “Works with PCs”). We’ll update this review—and our verdict—as soon as we get an evaluation unit.