Prior to computerisation, in the days when telephone switching was carried out by electromechanical switches, billing customers for usage was something of a nightmare.
Many different billing methods were employed worldwide, often requiring the electromechnical switches which made speech possible to be overlaid with a separate billing system to collect data.
In the days when step-by-step (Strowger) switching dominated the world’s telephone networks, there were two levels of billing employed – an access charge and an actual usage charge. The access charge usually took the form of a monthly rental, and customers were called subscribers – as they “subscribed” to the telephone service. This covered the cost of supplying the infrastructure and its maintenance, including switches, lines, poles, power and staff salaries.
The usage charge, which roughly recorded the number of calls made and/or the length of the conversation required the use of meter pulses and electromechanical meters. These meters were a series of discs with numbers from 0 to 9 printed or embossed around their edge. As each meter pulse was received, the units counter would step on by one number. As it reached nine, a small cam would engage the adjacent disk and rotate it by one position as the unit counter stepped round to 0 under the influence of the next meter pulse, much as a car’s odometer records distance travelled. Strowger meters generally counted to 5 decimal places so a typical meter could read, say, 23679 until the next pulse clicked it over to 23680.
The use of meter pulses enabled different charge rates to be used. A standard rate for local calls, a pulse at a faster rate for calls to nearby exchanges, and a pulse at an even faster rate for long distance calls. In smaller exchanges, the meters were arranged in racks within the switchroom but, at large exchanges, the meter room was a separate locked room as the information contained therein was obviously valuable. Compared with the switchroom, the meter room was a haven of peace where the quiet was interrupted by the meter pulses of active subscriber lines created clicking sounds – much like the old pulsed clocks that were so popular in government buildings in the 1970s.
The meters were rarely read by hand. Usually a camera with a specially designed and illuminated shroud was placed over the face of the meters and a photo of the meter count was taken. The photographer would proceed across the face of the meter racks, photographing the meters in large blocks.
Once developed, the image of the meter readings could be projected onto a screen, much like we project and magnify the images from microfiche today. A punch-card operator would then key the readings into a punch machine for batch processing via some of the early invoicing computers.
I recall one English technician whom I worked with in the early days describing a verbal altercation that had occurred between a colleague and a subscriber in the UK some years before. Things had become somewhat heated, but the technician had the last laugh. He went around to the meter rack, slipped the metal can off the subscriber’s meter and happily tapped away on the armature until he felt better, thereby ratcheting up many more meter pulses than the subscriber warranted, and increasing his bill.
I believe that Strowger metering was used in New Zealand for a short while, but cannot verify this. However, the high overhead in reading and processing meter data was not justified, and unmetered local calling was adopted until the arrival of crossbar and electronic telephone switching in the late 1970s.
This was the much touted “free local calling” that became enshrined in the Kiwi Share when Telecom was privatised some years back. However, free was a misnomer, as monthly subscription charges were adjusted to compensate for the lack of metered charging. Residential subscription rates were set at a point which reflected a lower calling rate when compared with business, and the fact that residential calling peaked in the evening which was outside business hours.
The concept of free local calling had become so entrenched in the New Zealand psyche, that residential connections had extraordinarily high calling rates compared with countries where metering was used. This meant that calling rates per line were very high at 10 a.m. when the busy hour occurred and surprised many of the Japanese when they were deploying their newly developed telephone exchanges here in the 1970s and 80s. There were some spectacular system crashes when exchange software and CPU’s simply couldn’t meet demand.
Unmetered local calling is still available for landline customers in New Zealand today. Other options which include different metered rates (with reduced monthly access fees) are also available. The modern telephone switch doesn’t rely on metered pulses but accurately times calls to the nearest second, and data is recorded for every call regardless of whether it is finally billed.