Alexander: Worldwide video chats not always a reality

QMy son lives and works in Bangkok, Thailand, so a video connection between us is important. When we use Skype video, it disconnects after a few minutes and never resumes. Both of our Internet connections and speed are OK. What can I do?

KIERAN BROADBENT, Ottawa

AIt's a measure of how far we've come that people now expect worldwide video calls to work. And they usually do, although the video isn't always full-motion.

But your video call must make a long trek on the Internet -- halfway around the world through a series of interconnected networks, some of them slowed by data congestion.

As I write this, Bangkok is among the top 10 cities for data congestion, as measured by Internet "latency," or delay. Check out today's worldwide Internet traffic delays at tinyurl.com/ytwysn (click "latency"; drag rectangular viewer around the world map).

Thailand is slow partly because some local Internet service providers have uneven quality (see tinyurl.com/7wrroxh.) Speeds sometimes drop below Skype's minimums for video: 256,000 bits per second (medium quality) or 512,000 (higher quality.) Many people there report Skype problems.

Ask your son try a different Thai Internet service, and try calling at different times of day to avoid Internet congestion.

BILL LOUK, Minneapolis

AThe company that scanned the original photos probably made a mistake in setting the "permission level" of the jpeg photo files.

My guess is that the color photo files were given "read and write" permission, meaning you can copy them from the disk to your hard drive. The black-and-white photos were given "read only" permission; they can be viewed but not copied.

Try changing the permission levels on the black-and-white photos by following Apple's instructions at tinyurl.com/68gxdk. After that, you should be able to copy the black-and-white photos from the CD to your hard drive.

If you can't change the permission levels, ask the company that scanned the original photos to replace the disk with one on which all files have their permission levels set to "read and write."