If you go to a wireless service provider’s store, you will likely see a network map showing the area they have under their cellular coverage. Infact these days you may find network maps showing coverage areas for 3G and 4G networks. In order to accurately map these coverage areas, service providers use what is known as ‘drive testing’. Network testers drive through different areas in vehicles equipped with spectrum analyzers and antennas and measure signal strength. Besides creating ‘number of bars’ signal strength maps, drive testing or wireless data collection can also be used to provide coverage analysis, determine network weakness information and aid in finding specific problem areas reported by consumers.

Some of the wireless service providers use an audio conference bridge in conjunction with such drive testing. A standard test signal is fed into an audio conference that is set up for ‘lecture mode’. In this mode the incoming signal is simply broadcast downstream. Different testers then dial into the conference using their cell phones and hear the test signal as they drive around. Since the test signal is a continuous tone, it helps them characterise where the signal becomes weak or is completely absent. They can also visit the spots where consumers complain about dropped calls and verify if that happens due to a weak signal or due to some other reason.

Modern audio conference bridges allow one to see a real time view of a running conference. Based on different thresholds for loudest speaker algorithm, the test supervisor can easily tell which routes have signal strength issues.

This approach of using a conference bridge for wireless signal strength testing can be cost effective and add a human angle to the test results.

Another side benefit of the real time display of the conference is that the test supervisor can tell which testers are dialed into the bridge and which ones are goofing off.

Many people look forward to a conference call with the same enthusiasm as a trip to the dentist. That’s because most people have had unpleasant experiences with their conference calls. Not surprising because large number of conference bridges out there are medicore or people attending the conference calls do not know how to use in-conference controls that may be available to them.

That’s pathetic, because audio conference calls are the most underused but highest value tool for helping a distributed team work together. While we are continuing to see many advances in desktop videoconferencing and Web-based conferencing, the fact is that audio conference calls are the simplest, cheapest, easiest way to bring a group together.

Modern bridges provide a number of features such as mute/unmute, mute all/ unmute all, self mute/ self un mute, enter conference muted, lock/ unlock, loudest speaker display, transfer to private room etc., that can make your conferencing experience pleasant. Some conference call bridges allow use of these functions via use of DTMF keys or via a web portal or both.

Next time you get on a conference call, ask the conference co-ordinator about what in-conference controls are available to you.

If you get a chance try to attend a analyst press conference. You can attand such a call in person or on a conference call. These are calls that a typical publicly traded company hosts every quarter. Usually the CFO and the CEO of the company are present. The meeting starts out with CFO or CEO giving the ‘state of the company’ speech. This is followed by a question and answer session with the financial analysts. During this session analysts from around the country or from around the world can ask questions about the performance of the company. Such Q&A sessons are usually managed by an event co-ordinator. The conference bridge being used to conduct such meetings allows the co-ordinator to tell which individual participant needs to ask a question and then allow or disallow the question based on contraints such as time avaialble, importance of the question etc. Some conference bridges allow an analyst to ask a question in private. The question is then filtered by the co-ordinator for relevancy and then asked in the conference.

Conference calling has become a routinely used service in the corporate world. Companies promote its use as it cuts down unneccessary travel, saves time and improves employee productivity. There are two ways a company can provide this capability to its employees. 

Managed Service: This refers to company buying audio conferencing service from a service provider. Most of the phone companies , large and small offer audio conferencing service these days. These companies then bill based on number of minutes used. The rates for conference calls range from 5 – 20 cents per minute based on number of minutes used. Typically the phone company also provides an 800 number for using the service. So the charge for long distance call is built into the per minute price.

On Premises Conference Bridge: This refers to a company deploying a conference bridge in its own network. The bridge is usually deployed behind a company’s PBX. A TIE trunk is required between the PBX and the bridge. Depending on the PBX and the conference bridge, the TIE trunk can be either based on TDM connection (CAS or PRI T1 or E1) or based on SIP/ H.323 connection. A on premises bridge makes sense when monthly conference usage goes above a few hundred Dollars per month. The conference bridges are sold on a per port basis. One port equates to one voice call. So a 24 port conference bridge can support up to 24 callers. These callers can be in one 24 party conference or four 6 party conferences or any combination in between. 

Owning a conference call bridge also means that you have to maintain it. Modern conference bridges provide web portals for this purpose and are usually easy to learn and use.

A distributed audio conference bridge refers to an architecture in which one or more TDM to VoIP media gateways are connected to a centrally located VoIP based audio conference bridge. For example, one could deploy 1000 port media gateways in 10 different cities and deploy a centrally located 10,000 port SIP/VoIP based conference bridge. People in different cities are a given a local DID that terminates on the local gateway. The gateway converts the voice signal from TDM format to packet based VoIP format. Such VoIP signals are then carried over a private data network that supports QoS towards the VoIP based conference bridge. The bridge in turn does the audio mixing needed for audio conferencing.

A ring down conference is used for bringing a group of first responders into an audio conference very quickly. Traditional ring down conferencing equipment makes use of analog FXS ports. For example such a system may be deployed at an airport or an Air Force Base. These systems are also called CrashNet Emergency Conferencing systems. The emergency ring down phones are clearly designated and located in specific areas. A person wanting a ring down conference simply has to go ‘off-hook’ on one such phone. The conference bridge detects the off hook and then immediately rings other phones connected to the bridge – hence the term ring down. As people pick up other phones they are placed into a conference with the initiator.

XOP Networks has extended the ring down bridging concept to VoIP based networks. It’s  <strong>SIP/VoIP based Ring Down bridge</strong> (Enhanced Firebar application running on SIP based USN) works in conjunction with an IP PBX. A person can go off-hook on pre-designated IP extension. The IP PBX will be programmed to send a SIP INVITE (equivalent to seeing an off-hook in the analog world) towards the XOP bridge. Based on that message the XOP equipment will immediately ring other pre-designated IP phones and upon off-hook place people into an audio conference.

for a audio conference, the current practise is for employees in India to dial into bridges in US. These calls require expensive international toll calls. A much cheaper arrangment is via bridge-to-bridge calling. In this case employees in India call into a bridge in India and employees in US call into a bridge in US. Then the moderator in US dials out from the US bridge and into the bridge in India. With this method one international call replaces multiple international calls and hence the savings. Based on the size of a conference, a typical customer can easily save 50+ % on the international conference calls with India.

XOP Networks equipment supports special bridge to bridge conferncing capability that can reduce the cost of international conference calls by 50+ percent. There is a white paper posted on XOP site that is very informative.

http://www.xopnetworks.com/literature/white-papers.html