The T1 (or T-1) carrier is the most commonly used digital line in the United States, Canada, and Japan. In these countries, it carries 24 pulse code modulation (PCM) signals using time-division multiplexing (TDM) at an overall rate of 1.544 million bits per second (Mbps). In the T-1 system, voice signals are sampled 8,000 times a second, and each sample is digitized into an 8-bit word.
Published in Chapter:
Interactive Multimedia Technologies for Distance Education Systems
Hakikur Rahman (SDNP, Bangladesh)
Copyright: © 2009
|Pages: 7
DOI: 10.4018/978-1-60566-014-1.ch100
Abstract
Information is typically stored, manipulated, delivered, and retrieved using a plethora of existing and emerging technologies. Businesses and organizations must adopt these emerging technologies to remain competitive. However, the evolution and progress of the technology (object orientation, high-speed networking, Internet, and so on) has been so rapid, that organizations are constantly facing new challenges in end-user training programs. These new technologies are impacting the whole organization, creating a paradigm shift which, in turn, enables them to do business in ways never possible before (Chatterjee & Jin, 1997). Information systems based on hypertext can be extended to include a wide range of data types, resulting in hypermedia, providing a new approach to information access with data storage devices, such as magnetic media, video disk, and compact disk. Along with alphanumeric data, today’s computer systems can handle text, graphics, and images, thus bringing audio and video into everyday use. DETF Report (2000) refers that technology can be classified into noninteractive and time-delayed interactive systems, and interactive distance learning systems. Noninteractive and time-delayed interactive systems include printed materials, correspondence, one-way radio, and television broadcasting. Interactive distance learning systems can be termed as “live interactive” or “stored interactive,” and range from satellite and compressed videoconferencing, to standalone computer-assisted instruction with two or more participants linked together, but situated in locations that are separated by time and/or place. Different types of telecommunications technology are available for the delivery of educational programs to single and multiple sites throughout disunited areas and locations. Diaz (1999) indicated that there are numerous multimedia technologies that can facilitate self-directed, practice-centered learning and meet the challenges of educational delivery to the adult learner. Though, delivering content via the WWW has been tormented by unreliability and inconsistency of information transfer, resulting in unacceptable delays and the inability to effectively deliver complex multimedia elements, including audio, video, and graphics. A CD/Web hybrid, a Web site on a compact disc (CD), combining the strengths of the CD-ROM and the WWW, can facilitate the delivery of multimedia elements by preserving connectivity, even at constricted bandwidth. Compressing a Web site onto a CD-ROM can reduce the amount of time that students spend interacting with a given technology, and can increase the amount of time they spend learning. University teaching and learning experiences are being replicated independently of time and place via appropriate technology-mediated learning processes, like the Internet, the Web, CD-ROM, and so on. However, it is possible to increase the educational gains possible by using the Internet while continuing to optimize the integration of other learning media and resources through interactive multimedia communications. Among other conventional interactive teaching methods, Interactive Multimedia Methods (IMMs) seems to be adopted as another mainstream in the path of distance learning system.