Check Your Cordless Phone Frequencies

Check Your Cordless Phone Frequencies
As we define in Part I of the book, the wireless frequencies at 2.4 GHz and 5.2
GHz are unlicensed, which means that you, as the buyer of an AP and operator
of a wireless broadcasting capability, don’t need to get permission from
the FCC to use these frequencies as long as you stay within certain power
and usage limitations as set by federal guidelines. It also means you don’t
have to pay any money to use the airwaves — because no license is required,
it doesn’t cost anything.
A lot of consumer manufacturers have taken advantage of these free radio
spectra and created various products for these unlicensed frequencies, such
as cordless phones, wireless A/V connection systems, RF remote controls,
wireless cameras, and so on.
A home that has grown up on RadioShack and X10.com gadgets can likely
have a fair amount of radio clutter on these frequencies in the home. This
clutter can cut into your performance. These sources of RF energy occasionally
block users and access points from accessing their shared air medium.
As home wireless LAN usage grows, there are more reports of interference
with home X10 networks, which use various wireless transmitters and signaling
over electrical lines to communicate among their connected devices. If
you have a home X10 network for your home automation and it starts acting
weird (like the lights go on and off, and you think your house is haunted),
consider your LAN as a potential problem source. A strong wireless LAN in
your house can be fatal to an X10 network.
At some point, you’ve got to get better control over these interferers, and
there aren’t a lot of options. First, you can change channels, like we mention
earlier in this chapter. Cordless phones, for instance, use channels just like
your local area network; you can change them so that they don’t cross paths
(wirelessly speaking) with your data heading towards the Internet.
Second, you can change phones. If you have an 802.11b or g network operating
at home on the 2.4 GHz band, consider one of the newer 5 GHz cordless
phones for your house. (Or vice versa: If you have an 802.11a, 5 GHz network,
get a 2.4 GHz phone). Note: An old-fashioned 900 MHz phone won’t interfere
with either.
You might find that your scratchy cordless phone improves substantially in
quality and that your LAN performance improves, too. Look for other devices
that can move to other frequencies or move to your 802.11 network itself. As
we discuss in Chapter 19, all sorts of devices are coming down the road that
will work over your 802.11 network and not compete with it. Ultimately, you
need to keep the airwaves relatively clear to optimize all your performance
issues.
At the end of the day, interference from sources outside your house is probably
your own fault. If your neighbor asks you how your wireless connection
works, lie and tell him or her that it works horribly. You don’t want your
neighbor getting one and sending any stray radio waves toward your network.
And do the same about cable modems. You don’t want your neighbor’s
traffic slowing you up because it’s a shared connection at the neighborhood
level. Interference is a sign of popularity — it means that a lot of other people
have caught on. So keep it your little secret.