Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: TUESDAY, October 18, 1994 TAG: 9410180088
SECTION: EXTRA PAGE: 3 EDITION: METRO
SOURCE: David Butler
DATELINE: LENGTH: Medium
A: Two types of cameras can be used as a door monitor - a miniature surveillance camera or a complete video intercom system. Either approach will enable you to check out visitors on a remote video display or television. Although more expensive, video intercoms include a dedicated wall-mounted display and support two-way voice.
Good quality surveillance cameras start at under $200 (B&W). If your home has a front porch or covered entry, you can hang a miniature camera from the ceiling. A conspicuous camera is a great deterrent to would-be burglars. Wall-box cameras with attractive weather-resistant face plates are also available. The style you choose may depend on finding a path to run the necessary wiring.
You can also use a surveillance camera to monitor a nursery or swimming pool. A small fixed-lens camera (table-top or wall-box) is great for a nursery. Although some models include a built-in microphone, you're better off using a separate baby monitor so you won't have to leave your TV tuned to the camera. A camera with an interchangeable-lens is usually best for a swimming pool, otherwise the field of view will be incorrect.
If you want to use more than one camera, you'll need either a modulator (one per camera) or a video switcher. A modulator places a camera's video signal on an unused television channel. This allows you to check all cameras from any TV in the house. A video switcher is less expensive, but you'll be limited to a single TV or monitor. A complete two-camera system can be installed for under $1,000.
Alternatively, you can opt for a video intercom system. As with a voice-only intercom, the front door box has a call button that serves as the doorbell. A small camera circuit is concealed behind the face plate, flanked by infrared lights for clear nighttime viewing. An electronic shutter compensates for widely varying daytime lighting conditions.
The indoor unit usually consists of a four inch video display and a telephone-type handset. The display automatically turns on when someone presses the call button. Most models also allow you activate the camera from the indoor unit - for example, in case you hear a noise. Another popular feature is a privacy mode that mutes the door box speaker.
Some video intercoms are designed to operate on an existing two-conductor doorbell wire. This greatly simplifies installation since ``fishing'' a video cable through an exterior wall - especially near a solid door jam - can challenge even the most experienced installer. In most cases, extending the wire from your existing door chime to a suitable monitor location is not a problem.
Options include voice-only stations for a whole-house system, an electric door strike (to remotely release a locked door), additional cameras and a video switcher. One system even includes a digital image recorder. Whether returning from a vacation or a day at the office, you'll always know who came to your door (or at least what they looked like!). Up to eight stored images can be recalled and viewed on the system's display screen along with a time and date stamp.
To receive a list of companies that manufacture video intercoms and surveillance cameras, please send $1.50 and a self-addressed envelope to David Butler F-429, Department TWN, 14713 Pleasant Hill Road, Charlotte, N.C. 28278-7927. The list includes toll-free phone numbers and a summary of each company's products.
Q: Is it possible to play audio compact discs on my DOS-based computer's CD-ROM drive even though I don't have a sound card?
A: Yes, as long as your CD-ROM drive has a headphone jack. With the appropriate disc-play utility (check the installation diskette that came with your CD-ROM drive), you can listen to music using Walkman-style headphones while working in another program. If the plug on your headphones is the wrong size, you can get an adapter at Radio Shack.
by CNB