Article : Communication becomes easier with VOIP

Do you want to utilize your Internet network more efficiently at no extra cost? Think VOIP! The Internet has proved to be a boon in many ways since its emergence and Voice over Internet Protocol (VOIP) can be counted among the advantages it offers. It involves using a single network for voice and data.

VOIP is also known as Internet telephony, Voice over Broadband, and Broadband telephony. It is a system that involves routing conversations over the Internet. Any other IP-based network may also be used for the purpose. The benefits and the drawbacks of VOIP are as follows:

Advantages

- You can receive calls on your VOIP phone even when you are on a trip. Just carry the phone; whenever you connect to the Internet you can receive calls

- VOIP to VOIP calls under most packages are free; VOIP to PSTN calls are, however, charged on the VOIP user

- Calls are treated as local calls. For example, if a call centre agent based in India calls a customer in New York, the call will be local.

- Some service providers offer free phone numbers that can be used with VOIP

- Value added services like caller ID, call forwarding, and automatic redial are included in many VOIP packages

- VOIP can integrate with audio and video conferencing as well as enable data transfer in parallel with the conversation

- Pre-paid cards can be availed

Shortcomings

- It is difficult to send faxes

- VOIP is entirely dependent on the quality and the reliability of the Internet connection; poor Internet connections can lead to low call quality and echoing

- On VOIP phones, you cannot make calls during a power cut, but you can receive calls

- It is difficult to identify the geographical location of the users and, therefore, to route emergency calls to the appropriate local call center

- It is possible to eavesdrop on VOIP conversations because most services providers do not offer encryption

- Caller ID information can be modified or spoofed and this can make it difficult to trace the caller

VOIP shortcomings are not insurmountable, for example, you can buy VOIP phones with a battery backup to ensure connectivity even during power outage. Similarly, business-grade VOIP services do not always rely on the Internet. They offer T1 connections, so you don't need to worry about Internet speed and reliability.

VOIP phones are increasingly being used by migrant workers and travelers who do not have a fixed phone and do not want to use their mobile because of high roaming charges.
However, it is also true that mobile phones are gaining increasing popularity among people in general, and many people use only mobiles and have no landline connection.

A fast and stable Internet connect is the primary prerequisite in this case

Article Source: http://www.articleboy.com/Article/VOIP---Communication-becomes-easier-with-VOIP/8865

Article : Virtual Classrooms

By: Rajesh Rastogi

A virtual classroom or VCR is a learning environment that exists exclusively in the form of digital content that is stored, and accessed through network of computers and information systems like PDAs, notebooks, mobiles etc.

Physical or Virtual Classrooms?

The main difference between the physical classroom and the virtual classroom is those of location, time and spaces required by students and teachers to access and partake in classroom activities. In the physical classroom a physical location must be visited at a fixed time in order to participate, while a virtual classroom is not physically accessed and has no real fixed time or location which is a great boon.

The manner in which a teacher delivers educational material remains an important factor in the success of both classrooms. Though both the classrooms employ similar learning theory, curriculum design and pedagogy, live face-to-face interaction is missing in the VCR method, which may have a negative influence.

May be the solution is the blended method where physical classroom training is combined with the virtual classroom training, thus accommodating a wider range of student needs.

As teaching in both the physical and virtual classroom is learner-centered, students learn by engaging in group work, projects, discussions, and other content relating to real-world contexts. The VCR is used to provide additional communication and material, along with the learning that occurs in the physical classroom.

VCR Tools
The important communication/participation VCR tools are
• E-mail
• Discussion boards
• Chat rooms
• Whiteboards
• Video/audio conferencing
• Instant messaging
• Podcasting/vodcasting
• Teleconferencing
• Weblogs
• Wikis
These tools can be further divided into two methods of learning Synchronous and Asynchronous learning.
Synchronous VCR Learning
Synchronous learning is communication or exchange of information at the same time between two or more people i.e. in real time. In virtual classrooms, synchronous communication is used by students to communicate with fellow class members and their teachers. This provides real time interaction and encourages group discussions. Chats, Video/audio conferencing, Podcasting/vodcasting, Teleconferencing are all Synchronous learning tools.
Asynchronous VCR learning
Asynchronous learning or communication does not occur in real-time, students or teachers are not present in the same space and time as each other. The instructions are delivered at one time and the work is done at a different time. Asynchronous learning allows the student to study at their own space and in their own time, plus both the teacher and the student benefit from because the entire discussion is recorded and can be repeated continuously. E-mail, discussion groups, whiteboards, wikis, weblogs, and forums are all Asynchronous learning tools.

Conclusion

The virtual classroom transcends the boundaries of location, time and space providing a flexible learning environment for all. Schools, universities and corporate organizations benefit form Virtual classrooms because it provides an excellent way for experts to teach a geographically dispersed group of students without hassle.

source : http://www.articleboy.com/Article/Virtual-Classrooms/24003

Article : Maximize The Results Of Your Online Web Meetings

By: Mostafa ElAwady

Before holding an online web meeting, you must be aware of the following:

1. Your online web meeting should be short and on track. The duration of the event should be no longer then one hour or maximum of one hour and thirty minutes.

2. What type of questions will you ask those attending the web meeting? Asking questions keeps everyone’s attention and allows you to effectively teach your guests.

3. As a courtesy to others in attendance, ask guests to hold their questions until the end of the meeting. Chances are that you will answer most questions during your presentation. Asking guests to hold their questions will reduce the overall meeting time for everyone.

4. Advise guests to preinstall the web meeting plugin before the live meeting. If guests will be speaking during a meeting, advise them to use the integrated audio setup and testing feature before the live meeting. Guests can perform this audio setup and test without logging in.

5. Prepare an optimized version of your PowerPoint® that is less than 2 MB. This will allow guests to see the presentation quickly and easily.

6. Always have a recording of your presentation available before a live meeting. Recorded presentations can be enjoyed by those unable to attend the live meeting. In the event a guest has a problem with their computer or internet connection, they can still enjoy the presentation. You may have invested thousands of dollars to promote your web meetings, and you lose time and money when someone can not attend the live meeting or has some problem that is beyond your control.

7. Practice your entire live presentation using the web meeting room program a minimum of 5 to 7 times from start to finish. This is the most important thing you need to know before holding an online web meeting.

8. Make sure the online web meeting service you are using offers free live training.

9. When it comes to web meetings, choosing the right service that meets your needs can be a daunting task. Make sure the program you choose meets the following important criteria:

• Login is fast and easy.
• Those with a dial-up connection can participate without problems.
• Web meeting program works with corporate firewalls.
• No Active-X control is required to run the program.
• You can easily create and manage live meeting polls and surveys.
• You can create and host your own custom registration pages.
• No scheduling is required, you can hold meetings anytime you decide.
• You can use any payment gateway to sell access to your meetings.
• The PowerPoint® presenter displays slides in dual format.
• Live video conferencing offers synchronized audio and video.
• Your guests can enjoy hands free meetings, you control everything they see.
• You can record and control your recorded presentations.

source : http://www.articleboy.com/Article/Maximize-The-Results-Of-Your-Online-Web-Meetings/24716

Video Conferencing

Introduction

In this article we will consider hard software for video conference communication. Among great variety of programs for video conference organization there are some the most famous which we are going to consider today - Microsoft NetMeeting, CU-SeeMe and Internet Phone 5. In the end you will be given results of the test made with a definite equipment. Here we won't touch upon such issues as coding of audio-video information and network aspects. In the appendix you can find explanations to some terms connected with a conception of video conferencing.

Equipment

The tests were carried out in a laboratory of network technologies with the following equipment in use.

Computer 1

Processor: Celeron-300 MHz
Memory: 64 MBytes
Video card: 3D Rage Pro AGP2X, 8 MBytes
Sound card: ESS 1938 PCI
Netcard: 3COM EtherLink 10/100 PCI TX NIC

Computer 2 (Compaq DeskPro XL5133)

Processor: Intel Pentium – 133 MHz
Memory: 32 MBytes
Bideo card: Matrox Millennium PCI, 2 MBytes
Sound card: Sound Blaster
Netcard: AMD PCNET Family Ethernet

Computer 3

Processor: Intel Pentium – 166MMX MHz
Memory: 32 MBytes
Video card: S3Virge, 2 MBytes
Sound card: ESS 1868
Netcard: Realtek 8029 PCI

Video camera Alaris QuickVideo DVC1

• Connection to computer via parallel port;
• Wide range of supported resolutions at high frame rate (up to 30 fps);
• Advanced software;
• OS – Windows 3.1x, 95 or NT;
• Manufacturer - Alaris

Video camera Creative WebCam 3

• Connects to USB port for easy Plug-and-Play installation – video capture card or external power supply are not required;
• Color video writes at 30 fps at 320x240 in 16 million colors, at 640X480 – up to 15 fps;
• OS – Windows 98;
• manufacturer - Creative

Card for video image capture VideoCap C210

• 32-Bit PCI Local Bus PnP 2.1 Compliant;
• 32K/64K/16.7M Color Mode Support;
• Plug and Play Compatible;
• OS – Windows 3.1, Windows 95;
• manufacturer - Tekram

The complete set for the first two video cameras includes software that allows to use all provided possibilities thoroughly. With these programs you can record a clip, make photos, postcards etc.

CU-SeeMe

CU-SeeMe packet is a program complex of video conferencing developed at Cornell University and promoted now by White Pine Software company. It's targeted at organization of video conferences on the Internet or on a corporate net with TCP/IP protocols support.

Its functional possibilities are quite typical:

• Realization of audio and video contacts between participants;
• Possibility of team-work with a document;
• File sending;
• Possibility to communicate during a conference by textual form (Chat Window);
• Possibility of organization of multy-point (group) conferences.

For group conferences you need a dedicated server, that is a reflector. One of the reflectors can be found here: http://www.dimensional.com/~bgodette/. This reflector works under OS Linux and allows up to 12 people communication. The program provides a convenient search of accessible servers for communication. As a rule, many of them belong to universities of different countries. There are both commercial and free versions of the product.

NetMeeting

Microsoft NetMeeting for Windows 9x and Windows NT serves as convenient means for holding conferences on the Internet and corporate networks. This program gives the same possibilities as the CU-SeeMe packet, plus it provides joint usage of applications. So, any Windows applications can be used by participants jointly what increases efficiency of work considerably. This is realized regardless of whether other participants possess an application provided by one of them for joint work.

The program ensures good video quality and offers minimum number of settings as compared to other programs. NetMeeting supports the standard of audio- and videoconferences H.323 which includes H.263 video codec. H.323 standard provides interaction of NetMeeting with other compatible programs of videotelephony clients such as Intel Internet Video Phone.

The master NetMeeting Resourse Kit allows to configure any program at option and create an installation file. This tool is quite useful if you need to set NetMeeting in a corporate network with uniform program settings.

Setup of Internet Locator Server allows to see other users and hold a videoconference if necessary.

InternetPhone 5

Internet Phone 5 program was developed by Vocaltec company.

The program supports transmission of images, voice mail functions, joint work on documents, file transmission and other possibilities. It will help you to find an interlocutor according to a communication language, interests and other features with an integrated VocalTec Community Browser.

Test results of hard software for video conferences

Our tests revealed serious differences among the products. The best of them were remarkable for simplicity in usage and worked flawlessly with different communication channels, even at "modem" data rates. The others appeared largely exacting, complicated in setup and worked bad via narrow-band communication channels.

While testing we used really existent communication channels (including the Internet), and we tried to enable all codecs of each packets. Data rate varied in the range between LAN speeds 100 Mbit/s and modem speeds 56,6 Kbit/s. As an image we used a standard background, first immovable the head started moving with the speed going up. All quality image changes were registerred. In the article we give average frame refresh rates received on the base of statistics gathered with the help of corresponding tools and confirmed with our visual observations.

The tests were carried out on the equipment mentioned above. Once again we should remind you of the configuration. The following testbed served for our tests:

• processor: Celeron 300 MHz;
• 64 MBytes RAM;
• Video card: ATI 3D Rage Pro AGP 8 MBytes;
• Sound card: ESS 1938 PCI;
• Netcard: 3COM EtherLink 10/100 PCI TX NIC.

The computer was connected to LAN 100 MBytes/s in order to be on the Internet. The other computers were used to test the products on the local network (10/100 MBytes/s). On each computer we installed OS Windows 98.

This basic platform was equipped with video cameras Alaris, Creative and Philips (with an image capture board VideoCap C210). The Alaris and Creative devices are the cheapest and the most popular for data transmission via the Internet. They don't require an image fixing board. The Alaris and Creative video cameras absorb a definite part of CPU resources, what can be a limiting factor for video codec performance.

For measuring memory size and processor load we used TaskInfo 2000 Version 2.2 Release program.

Camera	Fps	LT CPU, %	In Mem, KBytes	Total Mem, KBytes
Alaris	10	31	6576	18748
Creative	7	12	5740	18744
VideoCap	29	40	3844	18752

Table 1. Measurement results (CU-SeeMe program, White Pine H.263 codec).

Camera	Fps	LT CPU, %	In Mem, KBytes	Total Mem, KBytes
Alaris	13	90	5492	14188
Creative	15	26	5480	14188
VideoCap	15	77	1808	14268

Table 2. Measurement results (IP5 program, VVC1codec).

Camera	Fps	LT CPU, %	In Mem, KBytes	Total Mem, KBytes
Alaris	10	30	3732	10096

Table 3. Measurement results (Videogram Creator program, VGPX codec).

Camera	Fps	LT CPU, %	In Mem, KBytes	Total Mem, KBytes
Creative	30	40	1380	11172

Table 4. Measurement results (Video Blaster WebCam Control program, Vocaltec 263 Video Codec). As you can see each factor (codec, software, equipment) influences communication somehow.

The video camera with video capture card VideoCap C210 showed the best results (15-29 fps at 320X200, 16bit color). This results are demonstrated in the tables 1 and 2. Note that the results remained the same even on a weaker computer (2). At the same time, it's less exacting to memory.

The camera Alaris gave out images at the maximum of 10-13. This camera is limited by a parallel port via which it connects to the computer. Another downside is high load of the processor and the memory. Besides, the camera was tested with Videogram Creator, a program included in the complete set (see Table 3). This camera is not the best choice for video conference organization. It's good only for home use.

The Creative camera was capable to give 10-15 fps. The higher result was reached (30 fps) only with the software included in the complete set (Video Blaster WebCam Control) (Table 4). So, possibilities of the camera greatly depends on the power of the computer and the usable codecs in the programs of video conferencing. This camera was used only on the first computer because of an IR-port.

And concluding I'd like to make some recommendations concerning a choice of the video camera for conference communication. The specs of your computer would define exactly the required video equipment. The camera with video image capture board should be recommended for weak computers with a processor of Pentium class, though it may be used successfully on more powerful computers. If you have Pentium II or higher and USB-port at your disposal, we'd advise to buy a camera with USB-interface as the simplest in installation and ideal in "price/quality" ratio.

Once again we should remind you that the tests were carried out on local computers. How programs work on the net will be considered further.

Network	Program	Image	Sound
10 Mbit/s	CU-SeeMe	8-10 fps	satisfactory
	NetMeeting	satisfactory	good
100 Mbit/s	CU-SeeMe	10-14 fps	good
	CU-SeeMe + Reflector	10-14 fps	good
	NetMeeting	good	good

Table 5. Testing of hardware at different network bandwidth.

Note that NetMeeting can't determine fps quite exactly, so the data provided were achieved according to our visual observations.

This diagram demonstrates memory load of each program considered in this article.

Conclusion

The test results show that when working at the speeds of usual modems in analog telephone lines a user gets quite low quality of video image and audio signal. For such systems it's considered admissible if in narrow-band lines the frequency amounts 1-2 fps at 160x120 pixels. In wide-band communication lines, i.e. in the Ethernet (10 Mbit/s), the frequency rises up to 5-12 fps at the same resolution.

Usage of such medium as Ethernet 100 Mbit/s doesn't cause strong changes. Audio and video quality get improved slightly, however video conference system efficiency gets stronger in the presence of other applications on the net. Besides, such net usually doesn't feature any problems with joint usage of application programs and audit board.

What to choose? In case you are to organize video conferencing in a small office, you'd better take CU-SeeMe packet with an installed server-reflector and 100Mbit/s net bandwidth. Such combination is optimal as far as "price/quality" is concerned.

NetMeeting is more suitable for communication of separate clients using "faCe-to-faCe" dialogue. Possibility of integration of this program in Web-pages allows creating sites of certain direction, i.e. for distance studying.

Internet Phone 5 is a program aimed at home use allowing to find an interlocutor according to a communication language, interests, age, hobbies and other features. It's hardly useful for business work.

Appendix

Codec is hard software that converts analog signal into digital with the following converting of digital signal in order it can be transferred via more narrow-band communication channels (coding). At the receiving end a similar codec restores initial digital form and converts the signal into its analog form (decoding). Usage of such devices in equipment for video conference communication allows narrow-band lines.

H.261 is ITU-T recommendation "Video codec for audio/video data transfer in the channel P x 64 Kbit/s". P can change in the range of 1 to 30. Coding is based on transition prediction and usage of a code with variable length. The recommendation regulates coding algorithms for video transmission in CIF (352X288 pixels) and QCIF(176X144 pixels) formats at up to 30fps.

H.263 is ITU-T recommendation "Coding of video for low-speed communications"; it's a coding method developed for H.324 that uses H.261 technology with additional improvements.

H.323 is ITU-T recommendation "Videotelephone systems and terminal equipment for local networks with unwarranted service quality" (version 2 - "Multimedia communication systems for networks with commutation of packets"); it defines standards for video conference communication on local, corporate and global networks with packet commutation.

H.324 is ITU-T recommendation "Terminal for low-speed multimedia communication"; it defines standards for video conference communication with usage of plain old telephone service (POTS).

Videoconferencing is exchange of digital videoimages and sound among two or more distance parties. Transferred images can include video streams, immovable images of objects, data from graphics, files or applications. It allows participants to hear, to see and to collaborate in the real time mode with all their interlocutors.

source : digit-life http://www.digit-life.com/articles/videoconference/index.html