VoIP - Voice over IP. this is just a guess but I would assume that it is because you need a Internet connection to use it.
VoIP is used to transmit a voice signal via the internet. If you need such capability (internet phone, for example) then VoIP is required.
Yes you can use it but still you need to subscribe voip service from VoIP service provider.
There are many types of voip servers, these types depend on your requirments.Out of these types Voip through Asterisk is the best as it is opensource and cost efective solution for you need .For more details just check out http://www.asteriskgeekz.com
(VOIP is the wave of the future. IP Telephony means all you need is an Internet connection to use the phone. The downside is you need a good wireless VOIP router. What's good enough for surfing the net isn't good enough for VOIP. If you have one second interruption browsing the Internet, you probably won't even notice. If you have the same interruption on an IP phone, you just hung up on someone.
You need a VoIP modem or a computer to connect your phone and accessed your VoIP Server. Aditionally you also require an ATA adapter.
Of Course! Anyone can make a VOIP call. If you are using free services like Skype or Google Voice, then you just need to install the software, create an ID, dial the person on the other hand and start the conversation. If you are using a Hosted VOIP provider, you can make calls through your VOIP phone or the soft phone provided by your provider.
You may need to change your VoIP company, update the driver for your VoIP modem, or may need to purchase additional bandwidth through your Internet service provider. In some cases, you may need to actually replace your phone instead.
You recharge action VoIP through your credit card. You would just need to log into your VoIP account online and make the relevant payment and use the credit card option.
You need to install a VoIP phone system with supported fax feature.
Voip actually has their own personal website online that will guide you through everything you need to know about Voip; such as service providers and what all they exactly have to offer.
It is possible to use VOIP with a computer that has a microphone. You can also use specialized VOIP phones or adapters which allow your regular phones to use VOIP. The exact details depend on the different providers.