ISDN & DSL Broadband Connections
Thiago C. Gandarillas
ISSC 340
American Military University
Prof Kageorgis

Throughout this paper we will review all the concepts regarding the ISDN and DSL technologies, definition, usage, benefits overall and costs. We will also compare to newer technologies overall to understand where our connections capabilities were and where they are over today’s date and where it is going.
ISDN (Integrated Services for Digital Network) is a standard way to communicate digital transmission of data, voice, video and other network devices at the same at the same time over the traditional ‘’phone lines’’, basic telephone copper wires, called RJ-48 connectors. Prior to ISDN, the telephone system was only related to voice transportation, with very limited to none data service availability. The ISDN has the capability to support at least two or more connections at the same time, in any combination of voice, data, fax and video over a single line. At first ISDN speeds were only at max 128 kbits over download and upload speeds. Eventually carried over an E1, speed rates could be at 2048 kbps. (PC Magazine, 2001) ISDN-BRI (Basic Rate Interface), service is delivered through a pair of standard telephone copper wires at 128 kbps rate. Following available interfaces and their characteristics: * U Interface, usually a non-North American network, two wired interface between the network terminating unit and the exchange. * T Interface is a serial interface between a terminal adapter and a computer device, a digital very similar to a modem. * S Interface is usually implemented as a single interface called S/T on a NT1 (Network Termination 1), a four wire BUS that ISDN’s customer connect into. * R Interface is a definition that indicates the point between a terminal adapter and a non ISDN device that provide translation to and from the same device.
ISDN-BRI is very popular in Europe and also in Japan, but not so popular in North America. (CISCO, 2012) ISDN Primary Rate Interface (PRI), according to CISCO ‘’ is a service that offers 23 B channels and 1 D channel over Japan and North America overall, providing a total bit rate of 1.544 Mbps, while in Europe and Australia having 30 B channels and 1 D channel, providing a total interface rate of 2048 Mbps’’ (CISCO 2012). In North American countries PRI service is delivered throughout one or more T1 carrier, while in Japan it is used a similar circuit called J1. A T1 uses 24 channels of 64kbps in band signaling. For every individual channel that uses 56kb for voice and data, and 8kb for messaging and signaling. The use of PRI happen out of band signaling that provide 23B channels with a clear 64kb for data and voice and one 64kb D channel for messaging and signaling.
The use of PRI-ISDN is very popular worldwide through PBXs to PSTN technologies. PBX (Private Branch Exchange) is a telephone system that support a private organization to be concentrated in a central office line and intercommunicate within a large number of telephones stations within the organization. The central office lines provide connections and permits the shared use of these lines between all stations in the company. A public switched telephone network (PSTN) is pretty much our telephone network.
Over long-distance audio circuits, low-latency, high quality. ISDN is still a very reliable source or connection. Such as linking sports grounds, outside broadcasts into the main broadcast studio, remote studios overall. In the other hand, with internet access purposes, ISDN technology was mostly replaced by DSL technology in the early of the twenty first century, a technology that provides way more attractive speeds and at a very low cost compared to ISDN. [Digital Subscriber Line (DSL) is a technology that increases the digital capacity of ordinary telephone lines into the home or office. DSL speeds are attributed based on the distance between the customer and telco central office. There are two main categories. Asymmetric DSL (ADSL) which is used for internet access, where fast downstream is required, but slow upstream is acceptable. Symmetric DSL (SDSL) is designed for connections that require high speed in both directions.] (PC MAG, 2014)
ADSL (Asymmetric Digital Subscriber Line) is a technology of data communication that enable faster data transmissions over traditional copper lines used by telephones. Utilize frequencies that are not used by telephone calls. ADSL filter allows a single telephone to be used for both, voice calls and data transmission at the same time. It can generally only be transmitted within very short distances from the telephone exchange, overall within 2 miles, but it has been used in some cases over 5 miles. The data transported over ADSL technologies are usually routed over within the telephone company data network. It is the most common used type offered to home users, costs overall are very reasonable and even with a lower upstream speed, its downstream is very reasonable over customer necessity, which tend not to focus as much on upstream. (CISCO, 2012)
SDSL - Symmetric Digital Subscriber line is a non-standardized DSL that only supports data over a single line, not giving support to analog calls as the ADSL does. It flows over one pair of copper wires with usually a maximum range of ten thousand feet. SDSL usually range between T1/E1 and ADSL in price and it is mainly used by small and medium business that don’t need guarantees such as Frame Relay or higher performance leased lines. (CISCO, 2012) As a comparison DSL & ISDN technologies do require special types of modems, usually installed outside of the computer. Over ISDN, equipment could cost more and require a special digital telephone line. Both types of connections work with an external hard drive. While over Internet connection speeds could vary, depending on each computer and network equipment to be used. DSL & ISDN are quite efficient once comes to a regular browsing, checking email overall. ISDN have proven to be considerable faster than dial-up, allowing to files to be download fast and also providing high-quality streaming audio. It can also achieve connections of 128 kbps. In the other hand, DSL connections could in an average operate at 768 kbps or even faster rates. With larger downloads and high quality videos that difference becomes clear. (Gilmer, 2000)
A telephone service will be required over both technologies, if you have DSL or ISDN. According to Gilmer, ‘’Using a special digital telephone, ISDN allows digital voice audio rather than the analog audio of standard telephone service used with DSL. ISDN will not work in case of an electrical outage. DSL gives you the chance to keep all existing telephone equipment, wiring and ports, also gives you the possibility of usage of corded telephones in a case of power outages’’(Gilmer, 2000).
Internet access costs might vary depending up your local area of service required. The National Center for Education Statistics indicates that ISDN typically costs somewhat more than DSL. As the cases are not always the same, it is to each user best interest research what types of service and costs the local market might offer. Many companies tend to offer DSL which increase the competition in the market overall, bringing with that a very reasonable cost. (NCES, 2009)
The availability of both technologies, ISDN & DSL may vary, both technologies can’t be found in many places overall, where modem or dial-up connections could be available. One advantage of ISDN, you can use the same account to connect with any other line located in different places, in case of travel, while DSL requires one line per Internet access, so in case of going anywhere other than your home, another line, plan, ISP would be required.
Cable modem or cable internet access is another great product and with great presence on the market, bringing especially a big competition with DSL technology. The service provide Internet access via hybrid fiber coaxial wiring and is actually the same type of cable that carries television signals. With coaxial copper cables or fiber optic connectivity of a node to a cable drop is allowed. In a cable modem, customers in a neighborhood connected to a cable company central office. The cable company then connects to the Internet utilizing wide variety ways, usually digital satellite, microwave transmissions and fiber optic cable. Just as DSL, broadband cable connections provide a continuous connection with an Internet Service Provider. (CISCO, 2012)
Download speeds could be as much as 400 Mbps for business coustomers overall and 250 Mbps in residential areas overall in some countries. Uploads speeds could range from 384 kbps to over 20 Mbps in some cases. Broadband cable access in most of the cases show less usage over business because existing television cable networks that could by utilizing residential service and commercial building that do have the required wiring such as coaxial cable networks. Adding the fact, broadband cable customers share the same local line and communication may be intercepted by surrounding customers. (CISCO, 2012). Overall cable modem offers better speeds than DSL and ISDN, cable modem popularity is quite bigger than DSL and ISDN in the U.S. But in other countries DSL seems to hold the edge. Overall, DSL and Modem share millions of users all over the world, as the most popular broadband connection so far. In many cases the differences will not relate to technology only but with the internet service provider. And other factors like cost, reliability and quality of customer support for installation and maintenance as issues can exist.
One very promising technology that have been around mostly in business overall, it is just starting to spread in U.S home users, the fiber technology promises incredible high speeds such as 100x faster than Cable Modem and DSL connections. Google Fiber is a grand pioneer in this sector bringing fiber to home users, and not only offering a very appealing price for such speed, they are also bringing bundles including TV channels, so instead of having local TV places or DirecTV or DISH, as a main provider for TV channels. Google would also offer a very promising service for less costs overall, all through fiber, so no need of antennas such DirecTV and Dish use. (Google, 2014)
Optical fiber is a flexible, transparent fiber made of a superior quality glass (silica). It functions as a waveguide, transmitting light between both ends of the fiber. Fiber cable can also deliver electric current through its transportation. Overall fiber allows longer distances and higher bandwidths compared to wire cables. Over fiber cable connectivity instead of metal wire, signals travel along them with a lot less loss of signal and also do not present electromagnetic interference as metal wire does. (CISCO, 2012).
As most people might not realize that fiber optic is far from only Internet Access usage,
It could be used for Security Camera Applications, Fiber to the Workstation and Fiber Optic and Intelligent Transportation. Security Camera Applications, as a network of several IP security cameras installed in a parking garage for example. Cameras could reach as far as 1000 meters away from the equipment room and do not need local power installed. With power over the Ethernet possibilities, fiber technology offers data and power over a single cable. Fiber to the Workstation, bringing fiber to the work area, for VoIp phones or just for the security that fiber optics brings to the network overall for example, FTTD can be accomplished. Fiber technology offers, flexibility, speed and security that many organizations might need. Fiber Optics and Intelligent Transportation (ITS), applying communication and information technology in providing solutions for congestions as well as over control over traffic issues. It ranges from real time traffic conditions to sensors for weather conditions to link booth information. Things like variable message signs, accidents, speed limit changes or delays. This technology can also control the flow of traffic, via traffic signals or by opening and closing special lanes based on traffic conditions. Video surveillance cameras are also a big role of the ITS capabilities, adding to the network bandwidth demands.
Regardless of its function, fiber optic overall offers an incredible valuable component over the traffic network infrastructure. Modern ITS networks are required more and more, data rates to facilitate real time communication between a large varieties of devices remote connected and traffic control centers. Fiber based ITS structures uses a combination of coax and twisted pair wire for both, video and data transmission requirements in areas all around the world. Video transmission over intersections, through surveillance, ramps, tunnels, incident detection or verification, and replacement of traffic signal loop sensors are areas of a great potential in the market. All of those applications require certain distance between the site where the information is and the location where the information is to be stored. Fiber optic connection provide better bandwidth, greater transmission distances and more signal immunity. (FiberC, 2014) In the Fiber optic field the potential is incredible. We could list many more points of a great impact of this technology. It is amazing be able to presence all that revolution over connection capabilities, medium and speeds. Some of us were maybe able to presence the use of dial up around the 80’s and 90’s with a bare minimum speed connection of 33.6 kbps, eventually the start of DSL where speeds jumped to an average of 3 Mbps at first, getting higher rates eventually, then also Modem bringing average speeds even higher to around 30 Mbps, which over today’s date speeds can go even higher. So comparing those 33.6 kbps little over 15 years ago, with today’s Cable Modem average on 30 Mbps. It is an increase of almost 1000x faster than a little over 15 years ago. Fiber Optics is just around the corner home user’s wise, which promises to be 100x faster than today’s speeds. That is an amazing approximately 100,000x faster than less than two decades ago. Imagine what the future potentials are based on those numbers. It is very hard to tell all the possibilities not only over Internet Access but also technologies overall. (Mitchel, 2014)

References

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