Who you gonna call? Premium numbers, but a not-so-premium service

On Call Welcome to On Call, and a telephone mystery solved only after an innocent party found themselves on the receiving end of a most unexpected conversation.

Our story, from a reader Regomised as "Des", takes place in the closing years of the 20th century and concerns an IVR platform he'd developed.

IVR, or Interactive Voice Response, was the slightly inaccurate name given to the then exciting new technology whereby one might jab digits on one's phone to interact with a system on the other end of the line. Perhaps to leave a voicemail, make an order, or interact with any number of premium services.

Sure, such systems had been around for a while, but improvements in technology allowed all manner of creative endeavours to flourish back in those days. Alas, voice recognition was a tad rudimentary, but the tones emitted by the keys would usually do the trick.

As for Des, he'd sold a version of his platform to one of the UK's "premium rate" players. He'd popped in a 60-line system. There were two E1 circuits and a block of regional landline* numbers assigned. The customer had purchased a set of premium rate numbers and had them routed to the regional numbers. A simple system – customers would dial the ever-so-expensive number and be automatically connected to the service required.

"These were the kind of services aimed at the single male and advertised in such august publications as the Sunday Sport," explained Des delicately.

All went swimmingly until the inevitable support call came in.

"Apparently some company in London had complained that they were receiving calls from people who'd called one of these premium rate numbers," Des told us, "The callers were kind of upset that they weren't getting what they'd paid for, and the company's receptionist equally miffed at the nature of the calls she was having to field."

We can just imagine.

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The premium number company insisted its routing was fine, so Des investigated further.

"I called the premium rate number and got connected to their justifiably shirty receptionist."

OK – so the calls were definitely going to wrong place. Not so much Sultry of Southwark, more Angry of Angmering.

Working with the receptionist, Des began troubleshooting the problem: when had the problems started? What had been happening? What was the phone number the receptionist had answered...?

Aha. The number was identical to one of the numbers routed to the IVR platform, except that differed by a single digit.

He then dialled the company's number directly and, rather than the annoyed receptionist, found himself on the receiving end of an entirely different sort of telephone conversation. A bit more, er, specialist.

He called up the US telephone company to explain they'd managed to achieve something that successive UK governments had failed to do, and swapped inner and outer London*.

"Quite understandable," he added, "they were Americans after all."

Shortly after, normal service was resumed. The receptionist was spared unwanted calls, and the callers? One can but hope they also received whatever satisfaction they were seeking.

Telephone number routing can seem like magic to the uninitiated. But at least the on call number doesn't get directed to a premium line. Or does it? Confess all with an email to On Call. ®

Updated at 1206 UTC to add:

* The original version of this article referred to the 020 London area code, but this replacement had not yet happened at the time of the story. Our reader has since said they might have been mistaken, meaning the issue came about due to the one-digit difference between the 0171 code for inner London and the 0181 prefix for outer London.