Wireless Home Networking - Index of

Chapter 13: Using Your Wireless Network for Phone Calls
Wi-Fi VoIP phone manufacturers have (or are working on) similar partnerships
with hot spot providers to provide browserless access, so check the
documentation or Web site of your phone to see if yours does too.
A company to keep an eye on is Devicescape (www.devicescape.com). This
software company, based in the Silicon Valley area, is built around the
premise that non-PC devices need an easy way to get logged onto Wi-Fi networks.
The company currently offers beta versions of its supplicant software
(essentially security client software) for a number of non-PC platforms,
including Apple’s iPhone, some Nokia mobile phones, and (most appropriately
for this discussion) the Linksys WIP 300 Wi-Fi VoIP phone. Devicescape
is a startup, but they have plans to spread broadly throughout this market,
so keep an eye on their Web site if you need help getting online at hot spots
with your VoIP phone.
Choosing VoIP Wi-Fi phones
As mentioned, most VoIP services use SIP as the underlying technology for
their service. SIP is an international standard, which means it is widely used
and also relatively interoperable — a SIP phone is a SIP phone, no matter who
makes it and whether it’s wired, wireless, or embedded in your skull (which
doesn’t sound all that pleasant, but folks in labs are working on embedded
phones that will be with us always).
Because SIP is so standardized and widely used, manufacturers of Wi-Fi gear
(companies such as NETGEAR, Linksys, D-Link, Belkin, and SMC) are making
and selling SIP Wi-Fi phones that you can use with most major VoIP providers.
Skype does not use SIP (at least not in an interoperable way — Skype’s VoIP
protocols are their “secret sauce” and they’re not telling!). So the phones
we’re talking about here won’t work with your Skype account.
Consider the following when choosing a Wi-Fi VoIP phone:
� Wi-Fi standards supported: You’ll want a phone that supports at least
802.11g. As we write, no 802.11n Wi-Fi VoIP phones are on the market,
but we expect that eventually these will trickle onto the market and
replace the 802.11g models.
� Battery life: Battery life is a crucial issue with any cordless (or cellular)
phone. Unfortunately, Wi-Fi was not designed to be a low-power technology
suitable for use with small phone batteries. (It uses much more
power than, for example, a mobile phone radio system.) So battery life is
the Achilles’ heel of many Wi-Fi VoIP phones. Check the different manufacturers’
rated battery life, see how easy it is to recharge (many phones
come with a cradle you can drop them in, just as you do with a home
cordless phone), and see how easy it is to replace the battery should it
wear out.
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