Drawbacks
VoIP technology still has a few shortcomings that have led some to believe that it is not ready for widespread deployment. However, many industry analysts predicted that 2005 was the "Year of Inflection," where more IP PBX ports shipped than conventional digital PBX ports. This date has been moved on an annual basis and only now (mid 2006) is it beginning to happen. However, many purchasers of VoIP ports just want a phone, so the statistics can be misleading when interpreted by marketeers.Faxes
One drawback is the difficulty in sending faxes due to software and networking restraints in most home systems. However, an effort is underway to define an alternate IP-based solution for delivering Fax-over-IP, namely the T.38 protocol. Another possible solution to overcome the drawback is to treat the fax system as a message switching system which does not need real time data transmission - such as sending a fax as a email attachment (see iFax) or remote printout (see Internet Printing Protocol). The end system can completely buffer the incoming fax data before displaying or printing the fax image.
Internet Connection
Another drawback of VoIP service is its frequent reliance upon another separate service - an Internet connection. The quality and overall reliability of the phone connection is entirely reliant upon the quality, reliability, and speed of the internet connection which it is using. Shortcomings with internet connections and Internet Service Providers (ISPs) can cause a lot of grief with VoIP calls. Higher overall network latencies can lead to significantly reduced call quality and cause certain problems such as echoing.
VoIP isn't entirely reliant upon internet connections, however. VoIP systems can also utilize regular telephone lines and business-grade connections like T1 for voice service. A few business VoIP Providers offer dedicated point-to-point T1 connections, thereby not relying on an internet connection for service. Although residential VoIP service typically uses only an internet connection, business-grade VoIP service can use a variety of connection methods to provide ongoing phone service.
Many VoIP users still maintain a traditional analog voice line (business line) which allows them to dial emergency numbers and utilize a traditional fax machine.
Power Outages
Another drawback of VoIP is the inability to make phone calls during a power outage, but this problem also exists with many phones used with conventional land lines and can be remedied with a battery backup. During a power outage you also have the choice to forward your phone to your cell phone or another phone number so you would still be able to receive calls.
If VoIP is used in solitary LAN (with no internet connection), it would consume more resources compared to a PABX.
Modems are now available with lithium ion battery backup so that you can use the service with no power.
posted by cs @ 6:44 AM
