How WiFi Phones Operate

Everyone loves free things, and getting something you'd usually pay for at no cost is even better. This is one reason why people have embraced Voice over Internet Protocol (VoIP) for making phone calls. VoIP enables free calls, including long-distance and international ones. However, until recently, VoIP had one significant limitation—calls could only be made from a computer.

New phones now allow people to make VoIP calls without being tethered to a computer. WiFi phones use the same wireless technology that computers rely on, making VoIP much more portable.

This article delves into WiFi phones, exploring their features along with the advantages and disadvantages of using them. We will begin with a brief overview of VoIP and WiFi.

Grasping the concept of VoIP becomes easier when you have a basic understanding of how traditional telephones function. Most people are so familiar with using a regular "landline" phone that it feels automatic. You pick up the receiver, hear the dial tone, dial the number, chat, and hang up.

However, a lot occurs between dialing and the other person picking up the call. The conversation travels through the wires that make up the public switched telephone network (PSTN). Your local phone service provider directs the call through a series of physical switches that eventually connect your phone with the other person’s. This method is called circuit switching.

This process isn't the most efficient way to make calls. The circuit between both phones remains open during the conversation, even though only one person speaks at a time. It remains open even when neither is talking. (For more on circuit switching, see How Telephones Work.)

Wi-Fi phones are a part of the growing smartphone trend. Click here to learn more about smartphones.

VoIP, in contrast, operates using packet switching. We will explore packet switching and VoIP in more depth next.

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Packet Switching and VoIP

VoIP relies on packet switching rather than circuit switching. Instead of keeping a circuit open throughout the call, it divides the conversation into small packets of data. These packets are then sent over the Internet. Unlike circuit switching, packet switching only uses the network when necessary, transmitting data as required.

Imagine you and a friend, both using the same VoIP service, want to chat. You're using analog telephone adapters (ATAs) that allow you to connect your regular phones to your computers. Here’s how the process works:

It's an efficient system—never using the line unnecessarily—and it can be entirely free. If you’re using a service like Skype and calling someone with the same service, your call will cost nothing. But you might want to place calls away from your computer, or just move around while chatting.

With 802.11 networking, or WiFi, VoIP becomes wireless. A WiFi phone includes an antenna that communicates with a computer, base station, or wireless router via radio waves. The antenna at the base station or router captures the signal and transmits it over the Internet. You can learn more about this in How WiFi Works.

Let’s dive deeper into these phones and their features.

WiFi Phones

WiFi phones are similar to cell phones in both their interface and functionality. Much like a basic mobile phone, a WiFi phone contains a printed circuit board (PCB) that connects the following components:

Both WiFi phones and cell phones transmit and receive signals as radio waves. However, they operate on different frequencies. Cellular phones use frequency bands from 824 MHz to 894 MHz, while WiFi phones adhering to the 802.11b or 802.11g standards communicate at 2.4 GHz, and those using the 802.11a standard communicate at 5 GHz.

When making a call with a WiFi phone, you dial the number as you would with a regular mobile phone. If you're calling another VoIP user, you may be asked to enter a VoIP address instead of a phone number, depending on the specific requirements of your service provider.

The phone converts the number you dial into data packets, which it then transmits via radio waves to a wireless receiver. The receiver forwards the data over the Internet to the call processor, just like a standard VoIP call. When you start speaking, your voice is also converted into packets of data, which travel in a similar way to a VoIP call, though the specific process may vary depending on the provider.

Many WiFi phones are designed to work with specific services or networks. For instance, Netgear offers a WiFi phone tailored for Skype, while UTStarcom provides a model for Vonage. To use these phones, you'll need an account with the respective service provider, much like you would need a service plan from a cell phone carrier. The phone will either be configured by you or your provider to connect to the network.

Some WiFi phones are compatible with protocols rather than being locked to a specific network or provider. For example, ZyXEL and Linksys offer WiFi phones that use Session Initiation Protocol (SIP). SIP is one of many VoIP protocols – learn more about them at Protocols.com. After configuring a SIP phone, you can make calls by simply entering the recipient’s SIP address and pressing "Send."

SIP is an open protocol, meaning it's accessible to anyone. If you have a SIP address, you can contact anyone else with a SIP address for free. SIP is a widely-used standard for managing voice data, adopted by many VoIP providers, even if they maintain a closed network. Additionally, SIP can support other communication methods like instant messaging and video conferencing.

In the future, SIP is expected to enable seamless communication between various devices. This means that your computer, phone, PDA, and other communication tools could all be linked through a shared address book, allowing them to easily communicate with each other.

The Future of Wireless VoIP

WiFi phones have a lot of potential, but they’re not yet universally suitable. If you already own a cell phone and need a phone line for your DSL connection, you may not need another phone. Moreover, if you live in an area with limited WiFi access, finding places to use a WiFi phone could be challenging. For those without a network of friends using the same VoIP service, using a landline or cell phone may be a more cost-effective option.

However, as more cities roll out city-wide WiFi networks, WiFi phones will become more practical and beneficial. What once seemed like a novelty could evolve into a viable alternative to landlines and cell phones. This transformation could occur rapidly—the WiFi phone market saw a 76 percent increase in 2005, and experts predict it could double in 2006 [Source: Infonetics Research].

WiFi phones are already proving valuable in businesses and educational institutions. Many companies have integrated WiFi networks alongside VoIP services, which makes WiFi phones a promising substitute for traditional desk phones. College students, especially those living in campuses with robust WiFi networks, can also benefit from WiFi phones, enabling them to make calls at little to no cost.

Despite their potential, WiFi phones face limitations due to the newness of the technology and the lack of widespread WiFi coverage. There have been reports of certain bugs in newly launched devices that complicate their use. For instance, some phones restart whenever a user moves to a new WiFi network or if network settings are altered by an administrator. Some WiFi hotspots also require browser-based logins, which renders phones without built-in browsers ineffective in these environments.

Although VoIP doesn't consume significant bandwidth, other activities on public and corporate WiFi networks can. When multiple devices are using the same network, voice quality may suffer or calls may drop. Fortunately, newer WiFi networks can be designed to prioritize voice traffic. With the right hardware and software, these networks can segregate voice data, ensuring it gets prioritized and improving the overall quality of calls.