Remaining issue

January 2000 came. The first customer was already decided, and we had less than a month for the shipment judgment. Although LU development was in its final stage, there was a crucial technical issue remaining that had been giving us a headache ever since the beginning. It was a problem concerning detection error of DTMF (Dial Tone Multi Frequency) signals. It was a phenomenon that co-workers referred to as "missing or garbled numbers."

DTMF is the push-button signals or the series of beeps that are sounded to notify the telephone number to the switching equipment. Since asynchronous, narrow-band data communication was the basic environment of early VoIP, there was a concept of handling voice separately using protocol such as TCP/IP considering the amount of data and making sure voice was transmitted successfully. In the case of VoIP gateway, there is the need to distinguish with certainty PB signals from voice by monitoring the communication status to accurately transmit PB signals over an IP network. In other words, there was a mechanism for identifying PB signals and voice so that wrong PB signals are not sent to the other party when they are accidentally mixed.

In the case of an IP-PBX, however, there are cases when PB signals are received during transmission of voice guidance. Hence, there was the need to pursue contradictory issues of not recognizing PB signals in voice as PB signals, and detecting PB signals even with the presence of voice guidance when such signals are being passed through.

Unification of communication engineers, performing system design and signal processing engineers capable of tweaking with the inside of the DSP as the core of voice signal processing, played a major role in the successful development of IP stage, the first full IP-PBX in Japan. It was a project that consisted of developing the system while toying with the inside of devices. It is a good example of our company's policy of promoting the integration of technologies bearing fruit.

In other words, signal processing engineers in Shibaura did not know the events that could occur, but they would be able to find a mechanism as complete measure if such events can be accurately grasped. On the other hand, communication engineers understand communication and thus can inform the possible events to the signal processing engineers. And LSI engineers in Hachioji understood how such mechanisms can be accumulated. Integration of the technologies of these three parties resulted in the commercialization of the first full IP-PBX in Japan.

Signal processing tuning of VoIP-LSI took approximately two weeks. By this time, many of the developers starting with Koji the Sub-Team Leader were confident in that the product would be complete for shipment. Although there are many developments that never make it into the market, I, too, was confident that this product would be released soon from experience.

Two days before the shipment judgment. And something had occurred.

Sharp pain

That morning, I woke to a sharp pain racing through my back. The pain was so intense that I broke out in a nervous sweat. Just then, I remember the change in my health condition five months ago. It's probably that. Fighting the dreadful pain, I thought about the shipment judgment meeting that was to be held in two days.