When you place a traditional call from your home telephone, analog voice is transmitted over circuits supported by your phone company's Public Switched Telephone Network (PSTN). When you place a call from a VoIP phone, voice is encoded into a stream of IP packets. Those packets may be relayed over your company's own private network or the public Internet.
With traditional telephony, you pay the phone company to carry each call over the PSTN. With VoIP, you pay for the underlying IP network -- for example, if you're already paying for an Internet connection, then VoIP calls are "free." Of course, they are not really free, but you may leverage capacity and equipment in your existing network to reduce your total telecommunications costs. In particular, VoIP calls avoid toll charges associated with long distance calls, because it costs no more to send IP to Paris than to send IP to your next door neighbor.
A traditional analog phone is plugged into an RJ-11 telephone jack that leads (eventually) to the PSTN. A VoIP phone is plugged into an RJ-45 Ethernet jack that leads to an IP network. A VoWLAN phone simply makes VoIP more convenient by using 802.11 wireless to eliminate that Ethernet cable. With a desktop VoIP phone, you're tethered to your desk, just as you are with a traditional desk phone. With a VoWLAN handset, you are free to move around your building, making and receiving calls anywhere there is 802.11 wireless coverage.
But what happens when you leave your office? A single-mode 802.11 phone won't work if you don't have WLAN coverage -- but a dual-mode phone could let you continue your call on a cellular carrier's network. Perhaps someday soon, you won't have a traditional phone on your desk and a cellphone on your belt -- you'll carry one IP phone that works over WLAN when you're at the office and WWAN everywhere else. To learn more about VoIP in general and VoWLAN in particular, visit SearchNetworking's VoIP Learning Guide.
Dig Deeper on Wireless LAN (WLAN)
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