of voltage conversion and regulation with surge protection (zidong xiaoliu wen ya dian yuan). They are rather expensive, however. Regardless of which system you use, note that transformers become quite hot when left plugged in and may burn out if overheated. If you are planning to use your computer or other equipment requiring a transformer for long periods, training a fan on it will keep it cool. Otherwise, the transformer should be unplugged when not in use.

Bringing in a desktop computer is more cumbersome than bringing in a laptop and is more difficult to get through customs. Some people recommend buying one in China, where the prices, particularly in Beijing, are now only somewhat more expensive than in the United States. Advantages of desktop computers include the larger, easier-to read screen and the fact that many Chinese work units use them. You could also buy a screen in China and plug it into the video port on your laptop. If your desktop unit includes a port for a 5 1/2" disk, which is most commonly used in China, you will avoid the problem of transferring data on different-sized disks back and forth between your own machine and those of your work unit.

In large Chinese cities, brown-outs are not as common as they once were. However, if you do use a desktop computer it is advisable to have a back-up power supply to protect your data against brown-outs. An uninterruptible power supply (UPS) can be bought in China for several hundred dollars. Although most do not have the capacity to supply electricity for more than a few minutes, they will give you enough time to save your data and turn off the machine before the data are destroyed.

Setting up a printer in China can be problematic, because successful operation requires conversion of both volts and cycles. A few brands, such as Canon Bubble Jet, have portable models that run on both 110 volts 60 Hz and 220 volts 50 Hz. Many people suggest buying a printer in Hong Kong, where you will pay about ten percent extra for the 220/50 capacity.

As mentioned above, long-lasting batteries are difficult to find in many parts of China. Researchers using nickel cadmium batteries, which can be recharged, report that they need to be drained frequently when using a transformer. Some people prefer to use short-lived batteries and keep an ample supply on hand. They warn, however, that batteries can lose power suddenly, so it is necessary to save every page.

Since computers have come into wider use in China, it is now possible both to purchase and repair them in some cities. Large foreign computer companies have offices in major cities, and the Haidian district of Beijing has several computer shops selling disks, programs, and a variety of computer accessories. There is now a Computerland in Beijing, on Xizhimenwai Dajie, 1 Wenxingjie (phone 832-1279; fax 835