Technician blamed for cut phone calls

Press, 11 April 1989, Page 5

Technician blamed for cut phone calls

By

NIGEL MALTHUS

The Telecom Corporation blames human error for the Christchurch telephone exchange going “down” yesterday — the second time in four days. Calls were disrupted through the exchange between 10.30 a.m. and 10.50 a.m. yesterday. Last Thursday the exchange also had problems. Mr Brian Finn, the operations director for Telecom South, said yesterday’s "most unfortunate occurrence” was because of a technician not reacting to a coded print-out warning that the system was about to fail. At the time, the technician was putting in a “special condition” line for a customer, involving

a change to the computer software. That the computer could react by shutting down was a known software problem which had caused trouble in the past and which the manufacturer, N.E.C., had been working on.

The technician should have recognised the printout warning and stopped the operation, said Mr Finn. The result was a breakdown even in priority lines such as the 111 emergency lines.

Mr Finn said that traffic was exceptionally high after such a breakdown — when customers find their calls cut off, both parties usually try immediately to redial, leading to “a tremendous bowwave of traffic.”

The exchange was therefore phased back in gradually, between 10.38 a.m. and 10.50 a.m. The Christchurch exchange has been plagued with problems, more often because of overloading than bugs in the software.

Mr Finn said other centres had similar equipment, but the software was unique to Christchurch, being developed specifically for local needs.

The Christchurch system was also built “like Meccano sets” as capital development spending allowed, rather than all at once which was more usual overseas.

“It is very innovative, but there is a certain risk involved,” he said.