How Does a VoIP Call Work?

VoIP telephony is in the process of displacing traditional landlines, include digital trunks such as T1 and ISDN PRI. What is it that is different about VoIP phone calls and what advantages does this technology offer?

You’ll hear VoIP referred to as a network service rather than a telephone service. This is an important distinction for network engineers and business owners, but not of much concern to users. One telephone set looks pretty much like another. When you lift the handset, you expect to hear dial tone and be able to dial out. When the phone rings, you expect to pick up the handset and hear the party on the other end and have a conversation.

A lot of engineering work has gone into making VoIP phone calls mimic traditional landline telephone calls as much as possible. The ideal has been that you shouldn’t be able to tell a difference. Now that this goal has been generally achieved, the new ideal is to make VoIP calls sound more lifelike than anything you’ve heard through a telephone. It’s something called HD or high definition voice.

The telephone connection is what determines whether you are using traditional telephony or VoIP. A traditional analog telephone line is based on technology that goes back over a century. It consists of two copper wires twisted together that connect a particular phone all the way to the telephone company office and into the central switching system. This line has certain AC and DC voltages and other characteristics. Often the phone line provides power to the telephone set. The phone itself has evolved from electromechanical components to relatively simple electronics. It just needs to have the proper characteristics to interface with the analog line.

This carries over to in-house telephone systems such as Key telephones or Private Branch Exchange (PBX). These are small switching systems that handle internal calls to keep them off the public telephone network. The in-house phone system connects to each phone in the company with a pair of wires that mimic the line from the phone company.

VoIP uses your company computer network as its phone line. For this to work, the phone has to include circuitry that makes it look like a network peripheral and be compatible with everything else on the network, including computers, printers, servers and so on. Phones that do this are called IP phones or SIP phones. They have a standard RJ-45 Ethernet jack on the back of the phone to connect to the network. They can be powered over this same connection by special POE (Power over Ethernet) switches or have separate plug-in power supplies to operate the internal electronics.

Smaller companies and residential users of VoIP can use regular telephone sets by plugging them into an ATA or Analog Telephone Adapter. This adapter has the electronics that you would find inside an IP Telephone.

VoIP gets its name from Voice over Internet Protocol. That doesn’t mean it has to run on the Internet, although some low cost VoIP services do use the Internet as your line to the service provider in order to save money. IP or Internet Protocol describes the technology used by Ethernet Local Area Networks. It’s what makes the Internet work and also runs many networks that don’t connect to the public Internet.

Actually, it’s easier to achieve high voice quality by avoiding the public Internet completely and connecting to your phone service provider through an extension of your network called a SIP Trunk. SIP (Session Initiation Protocol) is the switching technology for VoIP systems. The SIP Trunk takes the place of the analog, T1 or ISDN PRI telephone line that normally goes to the local telephone company.

You can set up a VoIP telephone system in your company that shares your computer network, including any WAN (Wide Area Network) connections between business locations. You’ll install a IP PBX to handle switching calls between office phones and connect to your service provider for outside lines. A newer option is to skip the IP PBX and rent Hosted PBX telephone switching from the same service provider that connects you to the public phone system. This saves a major investment and allows you to add more phones as you need them.

Are you considering installing a new business phone system or expanding or replacing one you already have? Get features and pricing for hosted PBX and telephone trunking optionsto help decide what makes the most sense for your company.

Virtual Hosted PBX VoIP

There are various ways to implement VoIP. Some of them are excellent, others fall short of the mark. What you had in mind for VoIP in the first place was to save money and gain features. What you want to ensure is that the quality of your voice conversations will not suffer in the process.

That’s a tall order, but the technology is available to do exactly what you have in mind. The problem is that it can be a little tricky to get working properly. You can greatly increase your chances of having a successful implementation by getting some help with the installation. Not just by hiring a consultant, mind you. Move the tricky and expensive aspects of VoIP telephony to an expert provider and avoid the engineering and maintenance nightmare completely.

That’s the idea behind Virtual PBX systems, also called Hosted PBX. The PBX system itself has long been a fixture at most medium and larger size companies. There may not even be anyone on staff who remembers the day when all you had was a few phones and the telephone company took care of all that fancy switching. In a way, we’re moving back to that model of having just phones within the company and doing the connections elsewhere. The difference is mostly in the technology.

The first thing to know about virtual phone systems is the disappearance of the traditional telco wiring. That was the standard connection for analog telephones. Digital phones don’t need their own separate telephone network. They can ride along on the Ethernet LAN, along with all the computing equipment.

Phones do need a connection to your telephone service provider. That’s called a SIP Trunk. A SIP Trunk works like the ISDN PRI or T1 Phone line that connects to an in-house PBX system. The advantage of the SIP trunk is that it transports packets of all types. These can be voice packets from a telephone or data packets from the Internet. Some of the packets are switching signals for the telephones. They use a standard called Session Initiation Protocol which is where the term SIP comes from.

The phones that you use on the network are called IP phones. They look like a standard business phone with an RJ-45 network connector on the back in place of the usual telephone line jack. They are either powered by AC adaptors or over the network itself. This is called POE for Power over Ethernet. Some Ethernet switches offer this capability and save you the trouble of using AC adaptors. The switch can also provide battery backup so you can use your phones during a power outage.

The PBX system itself is located at the service provider. A hosted PBX or cloud PBX system is much larger than anything you’d buy for your own use. It’s operated and maintained by a dedicated staff so you don’t have to worry about outages, repairs or upgrades. What you have is a portal to that PBX system so that you can register your phones and decide on how the features work. All the in-house conversations are on the network so there aren’t per-minute charges. For calls that go outside, the hosted PBX has lines to the public telephone network. The economy of scale is so large that you can often get unlimited local and long distance calling as part of the per-seat monthly charge.

Are you considering a phone system installation, replacement or upgrade? Before you simply go the traditional route, check Virtual Hosted PBX VoIP service prices and see if it makes a lot more sense to rent rather than buy your business telephone system.