AT&T evolved into a hardware and software company that developed all of its own products from start to finish. By the 1980s, that trend was beginning to change and the evolution of the Conversant platform would mirror the change. The initial Conversant 1 Model 80 grew out of the heritage of products built for the AT&T network. The system consisted of a full height, six-foot TN/SN cabinet reused from AT&T’s Datakit product line. The top of the cabinet contained carriers for the Fastech TN/SN circuit packs, a standard for AT&T switches at that time. There was an analog crossbar switch card that connected the telephone interface cards with the signal processing cards. An IEEE 488 general-purpose interface bus (GPIB) card connected the switch and Fastech cards to the system controller, a Motorola single-board computer running the Unix operating system. A disk farm and massive redundant power supplies filled out the cabinet.
That original product was not only large but rather expensive. A Conversant Model 80 equipped with sixteen ports of analog “plain old telephone” (POTS) connections would run more than $150,000.
A slightly smaller physical package would emerge as the Conversant Model 32. This version retained the Fastech TN/SN cards but only a single card shelf in a much smaller physical configuration.
In the Model 32, the AT&T Terminal system console and the internal system control computer were replaced with an AT&T 6200 PC. With the single Fastech card cage, the Model 32 could not support as many telephone ports, but was significantly less expensive.
The next major evolution was to replace the AT&T manufactured PC with a more powerful PC built by Olivetti and to recast the telephony and signal processing cards as PC circuit cards adhering to the ISA bus standard. The fundamental telephony hardware was still designed by Bell Labs engineers and fabricated by Western Electric manufacturing, but key parts were being sourced from other manufacturers. This new version of Conversant, the Conversant 3, used an ISA card expansion chassis sourced from iBUS.
Conversant 3 would be the platform used for the FDR-IT Monday Night Football project. It would also find its way into the AT&T core network providing sequence calls for the SDN service’s NRA feature.
However, having a commercial brand of PC and an extension cabinet was not an elegant solution nor did it solve the problem of providing different sized platforms to achieve different price points. That gave rise to the innovative approach of supporting a range of integrated platforms, the Multi-Application Platform or MAP series — MAP/5, the small platform; MAP/40, the mid-sized platform; MAP/100, the large platform; and MAP/100C, the NEBS certified platform for us in telephone network central offices.
The self-contained MAP models would become the workhorse platforms for most of the rest of Conversant’s life. These computing chassis were sourced from an original equipment manufacturer, iBus. The Conversant engineering team provided the detailed specifications, but these platforms were outsourced. This gave the Conversant team control over the computing platform, something that was not possible using a PC vendor’s product and simply populating it with circuit cards and an extension cabinet.
However, the Conversant team’s control was limited. Computer platforms were already undergoing rapid change and innovation. With the core components such as CPU, RAM, and disk changing at least yearly, these platforms would have to be “updated” periodically. That led to continuous engineering activities specifying new components, testing them, and regression testing the Conversant software components against the new platform.
Eventually, a new series of platforms had to be introduced and they were known as the MAP/5P, MAP/40P, and MAP/100P. Although they superficially resembled the models they replaced, this constant churn was a headache for both Conversant and its customers.
The last platform created in Columbus was the UCS1000. This platform was designed to meet Network Equipment Building Standards (NEBS) which would permit its use in telephone company central offices. Unlike the MAP platforms that used ISA form factor cards, the UCS1000 was a Compact PCI chassis. Each of the circuit cards was developed in two parts: the primary functional part that was inserted from the front of the chassis and was hot-swappable, and the secondary part that hosted any of the peripheral connections the board required, e.g. T1 trunk, analog line, etc. Because the Compact PCI backplane had sufficient bus lines for both the computer bus and the internal telephone switching bus, no separate ribbon cable was required to connect each voice card. Because the peripheral connections attached to the smaller secondary “daughter card” at the rear of the chassis, once rack mounted, the UCS1000 did not be “unracked” for most repairs. If a circuit card “failed” that would usually be the primary card in the front. This was hot-swappable without uncabling the connections at the rear. Similarly, if changes were needed to a card’s connectivity, those changes could be made from the rear of the rack without accessing the front.