You probably never heard of a residential communication systems expert, and you may consider your household's communications needs to be nothing special. But these days even average households need such an expert when planning a new house.

How so? If you have a teenager who yaks on the phone a lot, a family member who works out of a home office and uses a fax, and another who likes to surf the World Wide Web, you know that even two or three phone lines often are not enough. Then there's the cable television that you want to have in more than one or two places in your next house. And an in-house computer network may not be on your radar screen yet, but it will be once every person in the house wants his own computer.

Why can't you just ask your builder to do a little extra wiring? Because although home builders appreciate the public's desire for houses with better communications capability, few have the expertise to deliver it, and most electricians are trained to install electric wiring, not these other systems.

The standard phone wiring that your builder is likely to install, unless instructed otherwise, is "4 conductor" wire. This has only a two-phone-line capacity. Even within the "conductor 4" category, there are gradations of quality that home buyers should be aware of, explained Gary and Boots Baumbaugh, home communication system experts in Sarasota, Fla.

It's not uncommon to find electricians using a cheaper type of "4 conductor" intended for burglar alarm systems. When it is used for a two-line telephone system in a house, conversations will "leak" from one line to the other when both lines are in use at the same time.

The Baumbaughs recommend at least "8 conductor, category 3, 24-gauge wire," which has a four-line capacity. But "12 conductor, category 5, 24 gauge-wire" with a six-line potential is even better, they said. The extra phone lines don't go unused for long, and the added capacity is nearly without cost. For 1,000 feet of wire, enough to do a 2,400-square-foot house, the six-line wire is only about $3 or $4 more than the two-line wire.

Having a phone jack where you will eventually need one is also critical, the Baumbaughs said. And, given all the uses for phones that we have now, a jack in each room of a new house is not excessive, they added. They even suggest two jacks in some rooms--for example, in the master bedroom, one on each side of the bed.

Instead of one continuous phone wire running from jack to jack throughout your house, the Baumbaughs advise a "home run" type of installation, in which a separate wire is run from a central phone box to each jack. This has two advantages: You can manipulate the wiring to add more phone lines, and any malfunction in a wire or jack will not disable your entire phone system.

For cable TV, home-run connections are also a must, the Baumbaughs said. Otherwise, the TV outlet at the end of the line will receive a weaker signal, and picture quality will be affected. At the point where the cable enters the house, you should also install an "amplifier" to enhance the cable signal before it gets dispersed to each outlet.

As with phone wiring, the quality of cable TV wiring can vary. The Baumbaughs recommend an "RG 6" type because the cheaper "RG 59" will not deliver picture quality as good.

With more and more services coming over cable, including Internet access and long-distance telephone service, a cable outlet in every room is also a good idea, the Baumbaughs said. Having the cable outlet and the phone jack in the same spot is especially convenient for Web TV, a popular option for households that want the Internet only for e-mail. The Internet is still accessed over the phone, but the TV screen can be used as a monitor, and a wireless keyboard is used.

Initially many clients resist adding a computer network to their new house because they think they won't ever need it, the Baumbaughs said. But a network avoids the computer slowdown that can occur when several family members want to access the Internet at the same time, and it eliminates expensive duplication of equipment such as printers and a large hard drive for each computer. A network also provides lightning protection.

What is a computer network? A system that hooks all the computers in the house to one main server. As with phone and cable, the computer network also requires home-run wiring--all the computers on the network need to be connected individually to the server--and the wiring should be "category 5-unshielded, twisted pair wiring," or "cat 5-utp." Cheaper wiring will cause the computers to be slow if more than one is used at the same time.

If you want to make changes to your system in the future or need to make repairs, it is helpful to have the "home base" for each of the three systems--

telephone, cable and computer--in the same spot. The garage will do, but a closet inside the house is optimal, the Baumbaughs said.

How much will all this wiring cost? For a new 2,500-square-foot house, the charge for installing the phone and cable TV wiring, 10 phone jacks and 10 cable outlets--enough for one in every room-- should be $500 to $600, the Baumbaughs said. Setting up a four-computer network would add about $500, they said.

Budgeting $1,000 for communication systems in your new house may seem excessive, especially if it means postponing luxuries such as the Corian countertops in the kitchen. But waiting to do this after a house is finished will cost three times as much, the Baumbaughs said. Even more disheartening, you may not get exactly what you want, because after the drywall goes up the installation work is much more difficult.

Katherine Salant can be contacted at Salantques@aol.com