by David Schinke
The Monday Night Football IVR application was going to be BIG. The customer, First Data Resources-Interactive Technologies or FDRIT, wanted to use a TV advertisement during the half-time of an NFL Monday Night Football game to stimulate people to call in. Callers could answer a question and potentially win a prize. I was not involved in the development of the application, or part of the Marketing/Sales process. My participation came at the point of installing the first tranche of equipment on a customer site in Omaha, Nebraska. But more about that a bit later.
“How many phone lines do you need to service incoming phone calls?” This was a question that Conversant IVR products faced throughout their existence. AT&T had worked this problem of “traffic engineering” for a long time, mostly based on how to provision network switching, transmission and customer premises PBX equipment. How many lines you need depends on the duration of a call, e.g. how much time, on average, this type of call takes to complete. It also depends on when the calls arrive at the destination equipment. Much of traffic engineering assumes random arrival times for calls following a Poisson distribution. There is a mathematical formula developed by a Danish telecom engineer named Erlang that computes the number of required ports based on two input quantities, total volume of calls expressed in a unit called Erlangs and the acceptable percentage of calls to be turned away (“busy signal”) when that maximum load is reached. This Erlang B formula is his primary accomplishment in this area.
In early customer applications, we sort of looked at some AT&T graphs, took a SWAG (an acronym for something unprintable in polite company) at the call durations, and offered the customer our best guess-timates. Follow-up with the customer’s real experience helped to answer the question but customers always wanted to know ahead of time. I am not a traffic engineer, and Dave Shain (one of our systems engineers) upbraided me for providing guess-timates to a marketing person. Dave Shain brought valuable traffic engineering expertise to Conversant.
The Monday Night Football IVR application was going to be BIG. AT&T was going to have to provide a substantial number of T1 digital trunks from the central office that served our customer. The final configuration would be about one hundred Conversant 3 “boxes” each supporting four T1 connections. This is just short of 1,000 telephone connections! It was decided to begin on the customer site with a small amount of equipment, some connected to the customer’s PBX, some connected directly to a small number of T1 trunks. We would also connect the “back-end” to the customer’s computer and verify that connection.
At this juncture, I had a reputation within the Dept. as “good with the customer” and “good with managing an installation”. So, a “hardware” person and I (a “software” person) went to Omaha to install the first tranche of equipment. I do not remember the line configuration, but I had some lines connected through their PBX and some direct T1 trunking. We did the usual drill of unboxing, arranging, mounting, and connecting equipment, starting up, loading software, checking-out hardware etc. Now it was time to “place a call,” which we did with a desk phone and “onesies” to each cabinet of equipment.
It was almost lunchtime, but this application would call for a heavy call load. How to be sure that the Conversants and the network trunks could handle it? Well, let’s just use one machine to test another. I had enough lines to load a T1 incoming trunk so I set up outgoing calls on 24 lines, and could place one incoming T1 trunk in service. Maybe two T1 trunks at a time for a total of 48 calls out and 48 calls coming in; I don’t remember. We “blasted” the network for about a half-hour to 45 min and verified end-to-end load capacity on all the equipment.
About 1:30 p.m. a customer technician we were working with came in and asked “Did you guys do anything in the last hour?”
“Yes,” I answered, explaining that we wanted to verify end-to-end performance for each trunk.
“That explains why people were having trouble making calls and getting incoming calls over lunch hour!” he said.
Through negligence, I had overloaded the customer’s PBX equipment and disrupted their phone service for the better part of an hour. I was very apologetic, stating that, “ It doesn’t have to be done again, and we are surely very sorry for the disruption.” The customer was somewhat understanding, although it did get mentioned to our management with no serious repercussions.
On a personal note, when it came time for the second and larger tranche of equipment to be installed, I asked to be relieved of the task of managing the installation. Perhaps I felt badly about disruption of customer service, perhaps I was simply tired of the travel, hotels, being away from family. I don’t clearly remember the reasons. Management agreed, enlisted Larry Whitacre for the task, and I didn’t do this type of work again until the voice messaging service application was installed in Jacksonville, FL.
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