|Sending voice over the internet
|Since the advent of internet
telephony, many residential offerings have evolved to compete with
traditional local and long distance telephone service providers. These
services save households money by using the public internet to bypass
traditional local loops and long distance lines. They send voice calls by
converting analog signals into digital packets that travel over the
internet. This type of transmission uses Voice over Internet Protocol
or Voice over IP (VoIP). The packets are then re-combined at their
destination back into voice so that you can converse with your called party.
|Common VoIP services in use today
Analog Telephone Adapter (ATA) - An
analog telephone adapter (ATA) allows you to connect a standard telephone
to the Internet. It essentially converts analog signals from your
traditional phone into digital data packets to transmit over the Internet.
ATAs are simple to use, easy to set up, inexpensive, and are a great
alternative to traditional home phone lines. Many major VoIP providers
like Vonage supply ATAs for free when you sign up for their services.
- Computer-to-Computer - Using VoIP
to make calls from computer to computer was the earliest form of internet
telephony. You just need the software, a headset with microphone or
speakers with a microphone, a sound card, and a good internet connection.
Typically there is no charge to make PC to PC calls, and the software can
even be downloaded for free. Common services include Skype and Yahoo!
- Hosted IP Phone Service - Hosted IP
phone services use a central IP softswitch that IP telephones connect to
over the internet. IP phones have the same appearance as normal
telephones, but instead of having a traditional phone jack, they have an
Ethernet connector. These phones connect directly to your Internet router
and contain all of the necessary technology to directly handle the IP
phone call; no conversion from analog to digital is necessary. The hosted
provider provisions the IP phones to connect to their IP softswitch so
that they can route your voice calls over the internet to your called
|How do businesses take advantage of
|Some businesses subscribe to VoIP services through
providers like Vonage or local cable companies. By connecting the analog
line ports of their current phone system directly to the VoIP service
providers ATA or analog gateways, businesses can convert their calls to VoIP and save on local
and long distance charges. These services disconnect your phone system from
the public switched telephone network (PSTN) and connect it to the
provider's IP network for call routing over the internet.
Another popular business VoIP service that is rapidly developing is SIP
trunking. Session Initiation Protocol (SIP) is a protocol used to for
controlling multimedia communication sessions such as voice and video calls
over the internet. SIP trunking is offered by Internet Telephony
Service Providers (ITSP). By using a SIP trunk, you disconnect your IP
PBX from the PSTN and connect it to the ITSP's IP network. This
network is connected to other private IP networks, the public internet, and
the PSTN. The ITSP will determine if your call is being made to a PSTN
number or to another SIP enabled phone system. It will then route your call
through the Internet to wherever it is directed.
Because a single SIP trunk can handle many
channels (voice conversations), it can process as many calls as traditional
digital services. SIP trunks have the potential of being a cheaper
alternative to both analog telephone lines and T1/PRI.
|Voice quality considerations
|Although quality of service is
still a hot topic, the quality of today's VoIP connections are quite good.
If you've used a VoIP softphone like Skype or Yahoo! Messenger then you may
have experienced issues like echo, latency (delayed speech), and diminished
sound quality. These problems are much less apparent on private IP
networks but can arise when the voice packets are traversing the public
internet. The best providers have large private IP networks and
usually provide better quality than providers that use the public internet
for most voice travel.
|Can my phone system handle VoIP
|Any PBX that can handle analog
telephone lines can be equipped with VoIP services that use ATAs or analog
gateways. The VoIP service is connected to the ATA, and the line is
connected directly to your PBX. SIP trunks are compatible with IP PBXs
that support SIP trunking. Most current IP PBX offerings support SIP
trunks and typically require licensing to activate this feature.
|When should I consider ordering
|VoIP lines can be a substitute
for both analog telephone lines and digital T1/PRI services. The
choice usually involves cost and features, but quality of service should
never be ignored. If your lines go down even for a few hours, the
savings of switching services may be lost. It is best to research your
provider's reviews on the internet and contact current users of the service.