Q I am experiencing a frustrating situation with my audio-video system. I have an Onkyo TX-SR606 receiver, a Sony Blu-ray player and a Sony Bravia HDTV. While watching HDTV from my cable box, I occasionally lose the audio-video signal for four to five seconds. There is no issue on non-HD signals, and some stations seem to be more affected than others. Blu-ray is not affected.

I use HDMI cables to connect my cable box and Blu-ray player to the receiver, and another HDMI cable to connect the receiver to the TV. The cable provider downplays the importance of the HDMI connection, and at its suggestion I have connected a second set of cables (component video -- red, blue, green -- plus an audio cable). The component-video picture quality doesn't look as good as HDMI. Do you have any suggestions?

RICH, MOON, PA.

A What you are experiencing is problems with the "HDMI handshake" that occurs when using HDMI connections. These connections incorporate High-bandwidth Digital Content Protection. HDCP is an anti-piracy measure implemented by software and hardware manufacturers. Unfortunately, HDCP often affects innocent consumers by causing viewing disruption and operational headaches.

Each of your components (receiver, cable box, Blu-ray player, HDTV) is HDCP-compliant. When a signal is sent over HDMI, the components communicate with one another to ensure all the devices are legal and compatible before allowing the audio-video signal to pass through. This communication protocol is referred to as the "HDMI handshake." If a successful handshake is not established, you will (usually) get a warning message saying you need HDCP-compliant equipment and the picture and sound will be disrupted. Because the component-video connections are not digital, they are unaffected. But as you have seen, HDMI offers superior picture quality.

Using the proper turn-on sequence can help establish a solid HDMI handshake. First turn on the TV, and let it run for a few seconds. Then turn on the receiver, and give it a few seconds to boot up. Then turn on the cable box and Blu-ray player. If the signal is cutting out while viewing, switching between TV or receiver inputs will often re-establish the handshake.

Given that the problem is only with the cable box, I suspect your provider is doing a poor job with its signals and equipment. Ask for an updated cable box.

I know of no components that are 100 percent free of handshake issues. It is unpredictable and components seem to have varying degrees of handshake issues when used together.

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