October 1997

Small-Density Voice/Fax Boards

BY PAULA JENSEN

Beware of the connotations sometimes attached to “small,” particularly when you turn your attention to small-scale voice/fax boards. You could, for example, get the impression that such boards are meant for special, limited uses. Not so. Small-scale voice/fax boards are eminently wellsuited for large, demanding (mission-critical) applications, as well as for complex, sophisticated communications systems. Consequently, “small” looms large in the voice/fax market. It will loom larger still as developers exploit the practical advantages of working with small-scale voice/fax boards.

ASSEMBLING LARGE-SCALE SYSTEMS WITH SMALL-SCALE BOARDS
Estimates for what constitutes a large-scale system vary. Some say the range is from 100 to 350 ports. Others would extend the range up to 1,000 ports. Although such capacities sound daunting, you can reach them with small-scale boards. What you need to do is install multiple boards in an industri-al class PC, or you can link together multiple PCs.

Industrial-class PCs have passive backplanes with approximately 20 slots. Thus, such PCs can accommodate the mother board, a network interface card, and as many CTI boards as needed to meet the required number of ports.

But what about ordinary PCs? Any XT or AT standalone PC can be configured with up to 64 ports using smalldensity, four-channel, voice/fax boards. PCs thus configured aren’t difficult to link together. The boards may have multiple, on-board DSPs (digital signal processors) for balanced processing and voice/fax integration at the hardware level.

All the same, it may seem that you could avoid linking together cards if you were to use large-density boards. However, even if you were to take the large-density route, you might still have to daisy-chain multiple cards. For example, you might find that few of the many ports in your large-density board were available for fax.

Of course, placing multiple boards under the control of a central processor has inherent speed limitations. On the other hand, what is lost in terms of time is gained in terms of better system integrity. Plus, you spend less for hardware and software when you increase capacity incrementally.

TACKLING LARGE-SCALE APPLICATIONS WITH SMALL-SCALE BOARDS
Do all large-scale applications demand immense parallel fax port capability, or can the same ends be achieved by different means? Consider an application such as broadcast fax. A large-scale user of fax, such as a political party, might engage in mass distribution of information for fund raising, polling, and the like. At first glance, it would seem broadcast fax is the quintessential largescale application. Yet fax broadcast may not require simultaneous transmission.

Often, mass faxing is done in batch mode, usually during off-peak periods to minimize line costs. Thus, simultaneous transmission may be unnecessary, which means faxes could be sent in serial groupings, either by individual or linked PCs. In any case, as mentioned earlier, daisy chaining of fax ports is also seen in some large-density systems.

EXPLOITING STANDARDS TRENDS WITH SMALL-SCALE BOARDS
Complex systems that incorporate large-density voice/fax boards are legacies of traditional telephony, where a top-tobottom developmental model prevailed. Clearly, this model still has a hold on telephony. However, it is being reversed, just as it was in the computer world. Now, standards such as the Telephony Application Programming Interface (TAPI) are promoting a new style of development, one which practically demands the use of small-density boards.

Traditional Development
Technological milestones typically emerge as large-scale applications. Get the most bang for the buck by accommodating the largest user, and then shrink it to fit the rest. However, migrating “mainframe” technology to a small, standalone machine is a complicated (and costly) process. The greater the number of interfaces that need to be written among an assortment of servers and clients, the greater the expense. The costs of hacking through proprietary thickets of interfaces and protocols are all too familiar in telephony.

For example, large-density board manufacturers depend on middleware servers for messaging between desktop CTI applications and leading telephone switches. The complexity increases when multinational corporations try to coordinate signaling protocols that differ from country to country and when they try to control a variety of network interfaces. Instead of having voice/fax functionality at the client’s fingertips, the large-density system acts as a conduit through multiple layers of hardware interfaces and software protocols to provide these services in a centralized, batch mode. Processing intelligence remains on the server.

Standards-Based Telephony Development
By embracing CTI, the computer world is assimilating all kinds of telephony devices, along with a mare’s nest of associated protocols. In this market, subscribing to the most popular telephony standards makes the most sense. Indeed, hardware that facilitates physical device connection while supporting the broadest application platform is a business imperative. For many, the standard of choice is TAPI.

TAPI, a set of functions supported by Microsoft, allows Windows applications (3.xx, 95, and NT) to program telephone line-based devices. These include analog and digital, single and multiline phones, modems, and fax machines. TAPI standards provide device independence: They facilitate hardware installation by allowing many Windows applications to share multiple telephony devices, regardless of manufacturer.

Individual device or service protocols and interfaces become a nonissue. Windows-based applications can transparently access information and network resources in a distributed computing environment. TAPI assigns the task of making these connections to the operating system, not the application. The complexity and variability of different telephone networks no longer requires hard coding. TAPI supports PBXs, ISDN, analog PSTN (Public Switched Telephone Network), cellular, CENTREX, and other types of telephone networks with an SPI, a service provider interface.

From a developer’s perspective, the TAPI device interface provides all the strategic design tools. If devices are supported by TAPI drivers, writing applications is simpler because the code becomes a common platform among these compatible devices. The developer writes to one TAPI standard, not to each specific telephone, modem or fax machine. This layer, in between the hardware and the application, facilitates upgrades. If physical functionality resides on the telephony device, it can be turned on or off by software. TAPI 2.0, which ships as part of Windows NT, is the latest release of the TAPI specification. Enhancements include: 32-bit architecture with 32 and 16-bit portability from earlier releases; Quality of Service (QoS) support; and an expanded set of features for call center applications. Continued support of TAPI insures portability and upward migration for CTI products.

CONCLUSION
Large-density boards are like luxury motor homes. Plush accessories and larger capacity add weight, and an appropriate engine is necessary to get them up to speed. It also requires an entire “pit crew” to maintain them. If they break down, every passenger is inconvenienced. Small-density boards are like sports cars. Fast and agile, these pieces of hardware are well-equipped to handle the road of market expectations, with all its sudden twists and turns. Smalldensity boards simplify upgrades and extend product life, for both hardware and software.

Small-density voice/fax boards have all the critical bells and whistles, common hardware and software interfaces, downloadable options, and guaranteed entry to the broadest application market. Thus, these boards allow voice/fax developers to minimize time-to-market, reduce development costs, and meet the expectations of an increasingly demanding CTI audience.

Paula Jensen is marketing communications manager for NewVoice, Inc., which manufactures feature-rich, fulland half-sized voice/fax cards. The NewVoice NVFX voice/fax boards deliver four ports of fax to the desktop. For more information on NewVoice, call 800-638-3647 or 908-684-1300 or visit the company’s Web site at www.newvoice.com.