Q Do some Blu-ray players have a problem reading certain discs even if the units have the latest firmware updates? I received a replacement movie disc for the first one that would not play, thinking it to be defective. But it, too, would not play on my Samsung player. It did play on an older Sony player.

A Yes, some Blu-ray players have problems with certain discs. The problem has existed since the format was launched. Although updating your player with the latest firmware is usually all you need to have a trouble-free experience, there are discs that have problems with certain players.

In March, CNET posted a feature called "Blu-ray compatibility: It's still an issue" (go to news.cnet.com and search for "Blu-ray compatibility"). It's worth a read for anyone who wants to learn more.

Manufacturers regularly release firmware updates to eliminate glitches as they are uncovered and improve the player's overall performance or add new features. For easy and automatic updates, buy a player with a wireless connection.

If you want the surest proof against playback issues, your best bet is to buy a PlayStation 3. It is still the most reliable, best-supported player on the market and has wireless connectivity to automatically download and install firmware updates.

If a component player is what you want, Panasonic players are reliable and perform well. The Panasonic DMP-BFD85 is a wonderful player with wireless connectivity; it sells for under $200. You can use the DMP-BD85's wireless adapter for updating firmware, streaming content from Netflix and more.

Although compatibility issues might exist from time to time with certain players and certain discs, it is no reason to shy away from Blu-ray. I've run into the problem only rarely.

Comcast update

I've been in touch with many readers and some PR representatives from Comcast, and I'm sorry to say that the A/B switch problem I've written about recently is far from resolved.

A familiar pattern has emerged. First, I receive an e-mail from a reader saying Comcast's representatives said that they do not have the switches and that a box must be bought to receive HD channels. I forward the reader's e-mail to the Comcast PR people, and a week or so later the reader gets the A/B switch.

But how many readers have contacted Comcast and were turned away but never contacted me?

The Comcast PR person I have been working with certainly seems to take the issue seriously and is working in good faith, but some of the reader comments are concerning. I will have more in an upcoming column, but in the meantime, if you were turned down for an A/B switch, please contact me through my website.

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