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A conference call is a telephone call in which the calling party wishes to have more than one called party listen in to the audio portion of the call. The conference calls may be designed to allow the called party to participate during the call, or the call may be set up so that the called party merely listens into the call and cannot speak. It is sometimes called ATC (Audio Tele-Conference).
Conference calls can be designed so that the calling party calls the other participants and adds them to the call; however, participants are usually able to call into the conference call themselves by dialing a telephone number that connects to a "conference bridge" (a specialized type of equipment that links telephone lines).
Companies commonly use a specialized service provider who maintains the conference bridge, or who provides the phone numbers and PIN codes that participants dial to access the meeting or conference call.
The more limited Three-way calling is available (usually at an extra charge) on home or office phone lines. For a three-way call, the first called party is dialed. Then the Hook flash button (or recall button) is pressed and the other called party's phone number is dialed. While it is ringing, flash / recall is pressed again to connect the three people together. This option allows callers to add a second outgoing call to an already connected call.
Businesses use conference calls daily to meet with remote parties, both internally and outside of their company. Common applications are client meetings or sales presentations, project meetings and updates, regular team meetings, training classes and communication to employees who work in different locations. Conference calling is viewed as a primary means of cutting travel costs and allowing workers to be more productive by not having to go out-of-office for meetings.
Conference calls are used by nearly all United States public corporations to report their quarterly results. These calls usually allow for questions from stock analysts and are called earnings calls. A standard conference call begins with a disclaimer stating that anything said in the duration of the call may be a forward-looking statement, and that results may vary significantly. The CEO, CFO, or Investor Relations officer then will read the company's quarterly report. Lastly, the call is opened for questions from analysts.
Conference calls are increasingly used in conjunction with web conferences, where presentations or documents are shared via the internet. This allows people on the call to view content such as corporate reports, sales figures and company data presented by one of the participants. The main benefit is that the presenter of the document can give clear explanations about details within the document, while others simultaneously view the presentation.
It is important to pay attention to conference call etiquette when participating; for example, one should refrain from shouting, multitasking in certain cases, and using an unpleasant tone. Care should also be taken to schedule a call at a convenient time.
Business conference calls are usually hosted or operator-assisted, with a variety of features. Billing is done through a variety of billing options.
Conference calls are also beginning to cross over into the world of podcasting and social networking, which in turn fosters new kinds of interaction patterns. Live streaming or broadcasting of conference calls allows a larger audience access to the call without dialing in to a bridge. In addition, organizers of conference calls can publish a dial-in number alongside the audio stream, creating potential for audience members to dial in and interact.
Party line 
Conference calls can also be used for entertainment or social purposes, such as the party line or a group call. Such entertainment-based conference calls are used to provide a break from boredom as well as a way to socialize with others. People call in to a specified telephone number and are connected to conversations with other callers. This serves as a way to talk to and perhaps, subsequently, meet new people.
In the "early" days (up to 1950's-1970's in some parts of Australia) a "party line" was the only way a community could make calls. Everyone was connected to the same line and all you had to do was pick up the handset and you would be connected. In some areas, the local operator could connect you by simply plugging in the lead to your house and you could join in the conversation. Interestingly the operator was able to listen to all calls, they would cut in and tell a caller if they were approaching their allocated time for a call. The operator was often a good source of information about the community.
Flat Rate Conferencing 
Flat rate conferencing services are being offered which give unlimited access to a conference bridge at a fixed monthly cost. Because telecommunication carriers offer free long distance bundled with local service, this alternative is gaining widespread popularity for budget conscious businesses and non-profits.
In the UK, there are conference services offered on a pay as you go basis where the cost of the phone calls (using 0843/0844, or 0871/0872 non-geographic revenue sharing numbers) from each of the participants covers the cost of the conference service. With this service type there is no monthly charge and usually no contracts to sign.
Prepaid conference calls 
Prepaid conference call services allow businesses and individuals to purchase conferencing services online, and conduct conference calls on a pay-as-you-go basis. Typically, a conference call PIN and its associated calling instructions are displayed immediately online after being purchased and/or sent via email. Generally, prepaid conference call services are used with a landline telephone, mobile phone, or computer, and there is no need to buy additional expensive telecommunications hardware or add/switch long distance service. Some services allow you to start or join a conference call from virtually any country worldwide—with appropriate telephone access.
Large telecommunications providers such as AT&T, Embarq (formerly Sprint), Verizon and other large to medium conferencing service providers maintain a dominant position in the conferencing niche; servicing many of the World's biggest brands. However, the Internet and improved global VoIP networks have helped to significantly reduce the barrier of entry into this niche.
Free conference calling 
Free conferencing is different from traditional conference calling in that it has no organizer fees and allows for multiple people to meet for the price of their long distance connections. Companies that provide free conference call services are usually compensated through a revenue sharing arrangement with the local phone company, sharing the terminating access charge for all incoming calls to a phone carrier.
Some background on the terminating access charge: On every long distance call in the United States including toll conference calls, the consumer is paying for origination (dial tone), transport, and termination (connecting the call). Each of these phone companies share a piece of the cost of the call. If it is the same phone company performing all three tasks (most likely the two largest phone companies - AT&T and Verizon), they keep all of the charge. This is known as Intercarrier Compensation (ICC) and is intended to keep the telecommunications system functioning by having every phone company receive compensation for using their network.
In the case of free conference calling, the conferencing company strikes an agreement with the local phone company that hosts the conferencing bridge to receive a share of the terminating access charge received for connecting the call. At large carriers such as AT&T and Verizon, they keep these access charges for their own conferencing services in addition to charging the customer for the conference service. With free conference calling, as mentioned above, there are no organizer fees so these services do not double dip: the consumer pays for a regular call with the same three components - origination, transport, and termination - of any call. In other words, the call costs the same as any other call under the customer's calling plan, but the conferencing is included for free to the host and participants of the conference call.
This added competition in the conferencing market has brought average rates down from over 20 cents per minute to under 10 cents per minute. In addition, it is more efficient and less expensive to speak to many people on one call (a conference call) than on multiple person-to-person calls.
In November 2011, The Federal Communications Commission (FCC) published a 732 page Order on InterCarrier Compensation (ICC), including rules governing revenue sharing. Citing Section 251(b)(5) of the Telecommunications Act or 1996, the FCC mandated that terminating access rates for all calls (not just conference calls) be leveled in 2012 and 2013, then reduced in three increments over the subsequent three years until they reach $0 in 2017. These mostly sub-1 cent charges are replaced with an Access Recovery Charge (ARC) that is added on to every customers' bill by their phone carriers. In other words, every phone company will get to keep the terminating access charges they had to pay out to connect each call while charging consumers more whether they make calls or not. This Order has been challenged at the Federal Appeals Court by several parties.
As for revenue sharing, the order adds a measure for high volume call traffic which triggers an immediate terminating access charge reduction to the lowest rate of any carrier in that state.
In the United Kingdom the 0870 prefix was originally used by UK-based free conference calling providers in order to receive a rebate from every call from telephone company that owns the number. However in April 2009 Ofcom, the independent regulator and competition authority for the UK communications industries, announced that the rebate that is payable to the telecom's supplier when an 0870 number is used would be removed. Systems were soon moved to 0844 and 0871 prefixes in order to retain the revenue sharing arrangement.
Premium conferencing 
Here participants dial in on a premium-rate number such as a toll free number in the US. The conference is typically hosted by the party that perceives value in the call in order to justify the cost: this could be a business owner, a non-profit board member, an educator, lawyer, or expert in any given field. That person then usually pays for the cost of the call. Premium conferencing can also be used for charitable fundraisers.
Premium Conferencing Feature Sets
- Reservationless or operator assisted conferencing
- Host PINs
- Name announce
- Roll-call (unique and superior)
- Moderator/participant codes
- Live web-based call management with mute/unmute, drop one/all, and dial out
- Recording with .wav file access through your online account
- High-quality on-demand transcriptions (with 4-hour turnaround on request)
- Customizable, "branded" greetings(unique)
- Broadcast mode
- Q&A facilitation
- Polling and polling reports
- Dial-out with or without requested response
Common causes of poor conference calls 
There are several common causes of poor quality conference calls:
- People simply not showing up.
- Lack of familiarity with behaviour and protocol.
- Lack of familiarity with equipment and technology.
- Background noise and disturbances.
- Poor coordination by call-initiator.
- Lack of moderator
Each of these causes requires a different kind of corrective action. However, there is usually one primary root cause; for example, people may not be showing up because the technology does not work, or the technology may not work because people are not familiar with it.
Technology problems tend to fall into two kinds: lack of bandwidth and poor equipment. Again, it is worth checking which of these apply in the case of technology problems.
Conferencing in IMS 
The 3rd Generation Partnership Project (3GPP) defined a technical specification (TS 24.147) for conferencing within the IP Multimedia Subsystem (IMS) based on the Session Initiation Protocol (SIP), SIP Events, the Session Description Protocol (SDP) and the Binary Floor Control Protocol (BFCP, aka RFC4582).
See also 
- "Conference Call Etiquettes". No Cost Conference Global. Retrieved 2013-04-30.
- Business Conference Call
- http://www.fcc.gov/document/fcc-releases-connect-america-fund-order-reforms-usficc-broadband, pg 215
- "New Ofcom rules should soon make it cheaper to call 0870 numbers". 2009-04-23. Retrieved 2010-05-17.