Cables RS232, Parallel, Category Patch, SCSI, IBM Patch, Video, Audio, Voice.

Networking Patch Panels, Hubs, Repeaters, Racks, Trancievers, Punchdown Blocks, Category Inserts, Wall Plates, Surface Boxes

Connectors D-Subminiature, Modular Plugs, BNC/Twinax, Fiber Optic, SCSI, Ribbon Mount, Panel Mount, Crimp/Solder, Network.

Bulk Wire Category Rated, Multi Pair, MultiConductor, Voice, Data, Coaxial, Fiber Optic, Twinaxial, Ribbon, Line Cord.

Accessories Switch Boxes, Line Boosters, Convertors, Surge Protectors, Splitters, Modular Adapters, Gender Changers, Adapters, Sharing Devices.

Terminators BNC, SCSI, VGA, PhoneNet, Twinaxial

History of Telecommunications
The original telephone system used analog signals to transmit a signal across telephone wires. The voice was carried by modulating an electric current with a wave form from a microphone. The receiving end would then vibrate a speaker coil for the sound to travel back to the ear through the air. Most telephones today still use this method. Computers, however, are digital machines. All information stored on them is represented by a bit, representing a zero or a one. Multiple bits are used to represent characters, which then can represent words, numbers, programs, etc. The analog signals are just varying voltages sent across the wires over time. The digital signals are represented as a positive or negative voltage changing over time.

The modem was certainly a big breakthrough in computer technology. It allowed computers to communicate with each other by converting their digital communications into an analog format to travel through the public phone network. But there is a limit to the amount of information that a common analog telephone line can hold. Currently, it is about 56 kbps.

ISDN
ISDN, which stands for integrated services digital network, is a system of digitizing phone networks which has been in the works for over a decade. This system allows audio, video, and text data to be transmitted simultaneously across the world using end-to-end digital connectivity.

ISDN allows multiple digital channels to be operated simultaneously through the same regular phone jack in a home or office. The change comes about when the telephone company's switches are upgraded to handle digital calls. Therefore, the same wiring can be used, but a different signal is transmitted across the line. Previously, it was necessary to have a phone line for each device you wished to use simultaneously. For example, one line each for the phone, fax, computer, and live video conference. Transferring a file to someone while talking on the phone, and seeing their live picture on a video screen would require several expensive phone lines. ISDN technically refers to a specific set of services provided through a limited and standardized set of interfaces. This architecture provides a number of integrated services currently provided by separate networks.

ISDN adds capabilities not found in standard phone service. The main feature is that instead of the phone company sending a ring voltage signal to ring the bell in your phone, it sends a digital package that tells who is calling (if available), what type of call it is (data/voice), and what number was dialed (if multiple numbers are used for a single line). ISDN phone equipment is then capable of making intelligent decisions on how to answer the call. In the case of a data call, baud rate and protocol information is also sent, making the connection instantaneous.

Many companies are using ISDN where service is not yet available. This is possible by using other digital communications methods at the local level. A common method is to use a T1 line, or a fractional T1 line to connect the computing facility to a switch that does provide ISDN access. A T1 line multiplexes twenty-four 64 kbps channels together over a single line. A fractional T1 line is simply a chosen portion of the full T1 circuit.

Switched 56 Digital Data
Switched 56: Unlike ISDN, this service is already offered by most carriers. It creates a virtual network over existing public phone lines with a 56 Kbps data rate. This service is cheap, but slow; therefore, it is ideal for intermittent data swapping between Wide Area Networks.

Switched 56 represents a fast, yet cost-efficient method of transferring data. The service taps the public network, taking advantage of the recent investments telephone companies have made in digital and fiber-optic communications.

The "56" of Switched 56 stands for the fast data rate of 56 kilobits per second. "Switched" refers to your ability to dial and receive switched data calls just as you would with a voice telephone line. Switched 56 combines high speed with the widespread availability and low usage cost of voice. Once Switched 56 is installed, you simply dial another user's Switched 56 number to transmit full duplex 56 Kbps digital data.

Switched 56 is a fast, inexpensive way to transport data digitally. Cost effectiveness. High speed. Widespread availability. Flexibility. Extensive Applications. For all these reasons, data communications managers, PC power users, LAN managers, broadcasters and video conference users are making Switched 56 the most popular of the Switched Digital Services.

Frame Relay
Is a dominant high-speed transmission technology. Many companies have turned to frame rely to replace there existing leased lines. Due to the excellent cost savings and flexibility it offers there are many advantage to this technology over competing technologies.

Cable Modems
Cable modems promises multimegabit-per-second speeds at less than $40 per month. This approach comes from neither the telephone nor the computer industries but from the cable television business.

However it is expected that when products and services become available they will be geared towards the consumer market first rather than the businesses. And, it remains to be seen the level of support systems the cable companies will be able to provide corporations.

T1 Line
In conventional telephone terms, a T-1 circuit carries up to 24 simultaneous 64 kbps voice conversations a total of 1.544 Mbps capacity.

If you're using switched services, like Switched 56 (a switched data service transmitting at 56 Kbps), you can use T-1 lines for about the same cost of Switched 56, depending on number of lines and distance between sites. In some cases you'll save money with T-1. In other cases you'll pay slightly more. The costs vary, depending on applications and network needs. Another neat network feature T-1 provides is user-defined bandwidth allocation. Managers can assign network resources and channels based on where and how they're needed.

Asynchronous Transfer Mode (ATM)
Asynchronous Transfer Mode (ATM) technology is emerging as an important worldwide standard for the transmission of information. Rapidly being deployed by telephone companies and enterprise customers, ATM represents for many the next generation for LAN switching. Its ability to accommodate the simultaneous transmission of data, voice and video is enabling a spectrum of new applications, including those supporting real-time voice and video.

ATM is a networking technology that has very high expectations to improve transmission speeds. It has the capability to condense and transmit video, voice and data over a single line. Its speeds far outrate those of LANs using Token Rings or Ethernet. However the speed does come with a higher price tag than traditional transmission alternatives. ATM is gaining hold in market niches, such as print production, video, and TV broadcast applications, medical imaging, financial transactions, and seismic analysis. Areas which companies need to move large amounts of data-quickly and where the need for speed far outweighs the higher price tag.

For technology managers, the variety of choices is only made more confusing by the emergence of ATM. Often it is very hard to determine the best alternative for a particular company's needs. There are more network choices than ever.

Applications of Telecommunications
Businesses have the potential to be the biggest winners in the future with the wide range of communication choices. It will be cost effective for companies to replace numerous existing analog lines with fewer ISDN, T1 or ATM lines that can handle multiple applications simultaneously. But for the average residential user, there are also many benefits.

One of the most talked about applications which needs lots of bandwidth is video conferencing. Previously, systems cost well over $100,000. Now the concept of personal, desktop video conferencing is available using common personal computers and workstations. One channel is used for voice, and the other channel is used for the display of moving video pictures. The price for video conferencing is dropping so quickly, that it is currently affordable to most businesses.

Along similar lines, is a shared electronic chalk board. Users can talk in a conference arrangement and also illustrate written ideas to remote locations. Slide presentations could also be given in this manner.