Integrating Data into Office Telecom Stream Provides Small- Office Alternative to LAN-PBX.
At the same time, they are searching for ways to handle the duality of the information flow--the recurring need for simultaneous communications between two people and the computers they are each using. Also, they are interested in being able to take advantage of all of the new data bases the computer information services now provide.
The choice is seemingly simple: two separate systems, a local-area computer network to carry data, and a PBX or a key telephone system to carry voice versus a single integrated voice-and-data system using standard telephone wiring, already in place.
For the small user, however, with need for no more than 120 ports for all voice and data communications, a complication arises immediately in planning for such systems. Rarely can organizations this size afford a dedicated professional expert in either telecommunications or data processing on staff to handle whatever complexities come along with the chosen system.
The need, then, is for a system that can be understood, installed, and maintained by "amateurs" who will not be devoting their entire working day to keeping the system up and running.
Recently introduced integrated voice and data communications systems can simplify all phases of melding local-area network capabilities into the same equipment that contains the voice channels, so that a dual alternative might rank as inappropriate for many small organizations.
There are a number of considerations and trade-offs in the process of deciding between separate systems or an integrated approach.
The most immediately apparent, and sometimes quite costly, factor is the choice of the communications medium. No matter which type of LAN is used, it requires the installation of cable of one kind or another in ducts, conduit or along walls, ceilings or baseboards. Furthermore, outlet connector plates must be mounted at each user location. In some jurisdictions, where the cable is governed by zoning ordinances, floor-to-floor risers may be owned by a communications company and not available for use.
The user then may be stuck with existing cable runs and have to install additional cabling when offices are rearranged or expanded. They must add to this the cabling already installed for the common PBX or KTS system.
Voice and data communications in an integrated system can be carried over existing two-pair telephone wire, simultaneously. Connections can be made using the existing modular wall connectors. Data communications capabilities can be added immediately without extra cabling, with all the resulting savings. Changes can be made conveniently. For example, the Telenoval system, designed specifically for small business establishments, features a station set with an identifying read-only-memory chip (ROM), that immediately advises the system when a change has been made. When the set is plugged in at a new location, all special features and security access levels are automatically changed to the new location.
Data transmission is another area that often causes confusion. Local-area networks using fiber optics boast speeds as high as 200 megabytes per second; baseband LANs offer speeds of from 1 to 10 Mb/s. An integrated voice-data system allows a bandwidth of 18.4 Mb/s. The local-area network speed is often a rather insignificant factor because the computer and disk or tape drives become the limiting elements of speed. With the integrated voice-data circuit-switching system, each data or voice connection has full-time command of its circuit.
Much data transmission over phone lines, when personal computers are involved, is handled at speeds of 300 to 1200 b/s. Higher allocation of bandwidths, dynamically assignable, will be useful when video and other kinds of advanced communications are brought into the system.
Data communications to the world outside a single building, or from network to network, is often handled through modems, and the attributes of a particular modem or the telephone lines are often the controlling factors in transmission speed. Data Needs Differ
Usually, a smaller organization's need do not include blinding speed, so that the convenience of the integrated voice-data approach outweighs the high burst speed rates possible in some local-area networks.
Another factor is the number of ports or nodes that can be served by a system. The Telenova 1, for example, serves 120 ports, and that total includes voice/data, voice-only, service, data-only and central office interfaces. Of course, PBX systems are virtually limitless, and local-area networks range from as few as five nodes to as many as 250. A planner trying to visualize a system that will handle present and future needs must take this size factor into account.
A potentially serious drawback to LANs, even in small offices, is the fact that the net can be accessed by only one user at a time. When the system gets busy, especially with heavy disk-access traffic, the whole network slows to unacceptable levels. An integrated system is able to handle all ports full time, so that the system is non-blocking. Integrated systems also offer full-time private circuit availability versus the daisy-chain shared option of LANs.
Connections to data devices affect both the cost and complexity of a system. The rule is the simpler, the cheaper. LANs require an often expensive interface card that is inserted into the computer, or some other separate server device, whereas the integrated system incorporates a data interface unit as part of its central module. In a LAN, separate external tap device and/or transceiver is required for the actual connection to a network, while a data adapter device simply slides into the station set in an integrated system like the Telenova 1. Computers and terminals with standard RS-232-C outputs plug directly into the data adapter device, so the computer is unmodified. This simplifies repair and warranty situations for the computers.
LANs are not standardized physically or electrically. This causes many of them to become obsolete or non-compatible with new terminal devices. The Telenova 1 incorporates standard circuit-switching that will be compatible with the coming world-standard Integrated Services Digital Network (ISDN).
Cost, which may be of more concern to the smaller organization, is a complex matter. Up-front costs may be higher with an integrated system because they include the central module, its interfaces and the station sets. However, other costs need be considered, such as costs of maintenance and service, costs for additions and changes, training time, actual use of system features and the like. A searching analysis of these "costs of ownership" over a five-year-old period should definitely favor the integrated approach.
The remaining factors to be assessed may all be considered together under the important heading of "user-friendliness." They include ease-of-use of the equipment and user time over the life of the equipment, ease of upgrade and modification of system functions, need for specialized training, complexities of service and diagnosis of problems, and single-vendor accountability.
First, a single integrated system involves only one vendor for virtually all of the components, whether voice or data, except for the computers and their peripherals. (With some exceptions, computers and peripherals usually come from different vendors than the LANs they're attached to). This obviously means service can be much simpler than when dealing with separate LAN and PBX vendors. Check for Diagnostics
Comprehensive diagnostics can be built into such a system to tell which part of it is malfunctioning. Service programs can then amputate the offending part from the system, leaving the remainder intact and unaffected. These diagnostics can be arranged so that they may be checked remotely, from a central service office, over phone lines.
If necessary, a trained technician in the central service office can advise someone on site what to do to bring that section back on-line. With the Telenova 1 system, for example, this could involve only replacing a printed-circuit board somewhere in the system, one that was easily identified by system diagnostics.
Single system also implies ease of learning, since the commonalities of the parts outweigh the differences. No matter which system is chosen, it will be used to its fullest only if it is completely geared to use by non-technical users. In the Telenova 1, for example, making a data connection has been designed to be as easy as making a phone call. In a company of any size, these are important things to take into account.
Some specifics of the system that make it unique center around the station set. It works much like a good interactive personal computer program, leading the user through its operation with a series of menus seen through a 40-character, two-line liquid-crystal display. This feature enabled us to build a set with only 25 keys, eliminating confusion and reducing the size of the unit. A set of five "soft keys" give only those choices that are logical and useful at a given moment. Thus the LCD offers transfer and conference capability at a push of a button after a call is connected. Before that, the same keys are used to select a common carrier or set up a data call.
We have found that this approach actually encourages people to use all of the features, since it removes the "fear of the new" that sometimes hamstrings our learning processes. There are no codes to remember or keys to re-label and a built-in HELP key provides instructions.
The unique network operating system (NOS) was written so that it can be used with more sophisticated integrated-circuit chips as they become available, helping owners of our systems avoid obsolescence.
This also means that it will be easy for the user, and us, to incorporate planned future expansions of the system for things such as videoconferencing, DS1 and X.25 interfacing, as they become readily available. The operating system also allows tailoring displays to vertical markets.
System upgrades are handled in software, and are provided on 5.25-inch floppy diskettes that anyone can load into the system for an instant improvement or added feature.
Based on this analysis, it can be safely said that for the small user, or the large user with smaller offices, the economics and efficiencies of voice-data integration offer more benefit and less liability than the dual approach.
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|Date:||Jul 1, 1984|
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