VoIP systems can deliver telephone service to standard analog telephones, to PBX- or key system-connected multi-featured phones, or to softphones built into acomputer with software. Softphones are software programs that display phonefeatures (hold button, caller ID, message waiting) on the computer screen and route the calls through a handset or an earphone and microphone wired to the computer. In addition to enabling VoIP phone capability with a minimum of new equipment (softphone programs work with standard PC peripheral audio components),softphones can also provide remote phone access. If the computer is a wireless laptop, then the softphone system goes with it anywhere within the range of wireless reception. For the home user, this extends the telephone system to the full limits of the wireless hubs on the LAN without the need to install cordless phones or carry any additional equipment.
Another means of extending telephone service to all parts of a home or yard is through the use of limited-range cordless phones. These phones are transceivers (transmitters and receivers) that operate on radio frequencies in the 900 MHz and 2.4 GHz bands. Calls on these phones are relayed back and forth between the wireless handset and the base unit in a two-way radio broadcast. The handsets are battery powered (usually by rechargeable batteries), but most base units require
AC power through a low-voltage transformer in addition to the line voltage in the telephone system.
Neither cordless phones nor wireless VoIP softphones are secure from eavesdropping by significantly interested parties. Calls on both types of phones can be received by anyone within range who has suitable equipment. The home user of wireless telephone equipment should be as careful as the business user not to give personal information, identification numbers, or any other nonpublic data over a wireless phone call.
Cell Phones
Cell phones can integrate with a home LAN either through their wireless connection to the home telephone system or via a connection to the Internet. A telephone link allows a cell phone to connect to the home LAN by calling a home land
telephone line and connecting through that call to other segments of the network.
With this link, the cell phone user can download information from the network's other nodes and forward command or control instructions to the security system, utility control systems, or other parts of the network.
The same objectives can be achieved by connecting to the home LAN through the Internet. Most cell phones now have a direct wireless link to the Internet through the service provider. Using this path, the home owner can link to the home LAN and perform all of the functions that would be available by linking to the LAN through a remote computer. Cell phone Internet connections are not as fast as a computer link, nor do they have the storage capacity or ease of data entry available on most laptops, but they offer great convenience for contacting the home LAN from any remote point where cell phone service is functional.
access point vs router
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