NBN reliability: Help guide first step for battery backup

An NBN optical network termination (ONT) unit with the battery replacement alarm on the right of the device

The roll out of the National Broadband Network is set to revolutionise the way Australians communicate, but it has raised questions about the reliability of the network compared with existing copper-based telephone systems, especially among non-technical people.

Earlier this year Computerworld reported the use of batteries in the on-premise equipment use to connect to the NBN has attracted the attention of the Greens political party regarding the potential environmental impact of some 11 million premises disposing of a battery every three to five years.

The cost and environmental impact are valid concerns about the NBN equipment, however, little investigation has been done into the risk to human life in the event of a power outage.

Today’s copper-based telephone systems, often referred to as POTS (plain old telephone service) do not require any form of secondary power to be able to make calls. While not infallible, POTS removes the necessity for the end-user to worry about power backups as the power supply is managed at the exchange.

POTS generally achieves “five nines” reliability (99.999%) which equates to about five minutes of downtime over a year – a good record for the new fibre-based NBN to aim for.

The arrival of optical network terminals (ONT) adds another device into the chain of telephone and internet services. If the ONT goes down, all landline services go with it.

A spokesperson for NBN Co said the government-owned organisation is going to provide its retail service providers (RSPs) a guide on maintenance of the power supply unit (PSU) and battery to give to customers.

“The PSU that houses the backup battery does have system of alarms and lights to indicate the state of battery,” the spokesperson said. “The terminals support a voice-only service which needs a standard phone plugged into unit and that port is what battery backup supports.”

With consumers notified when the battery self-test has failed, the only thing standing in the way of downtime is the availability of a replacement battery and the installation process, which is explained in the guide.

“The battery is designed to run for 5 hours but it also designed to suspend when at half-charge so it reserves the remaining capacity for an emergency,” the spokesperson said.

Anthony Merry, CTO and founder of Melbourne-based networking equipment vendor, Haliplex, said the issue of reliability also comes down to demarcation.

“Once upon a time the customer premises equipment (CPE) was powered from the exchange so changing batteries was someone else’s problem. Who will replace the battery on the CPE. It would be interesting to see the policy on this,” Merry said.

Merry said customers are “notoriously bad” at maintaining home appliances so “who’s responsibility is it at the end of the day?”

In the past Merry has expressed concerns about the reliability of the NBN core network in the event of a natural disaster.

“The issue is managing the transition in an open and diligent fashion. I’m sure NBN Co will be looking at a lot of these things. It will face a lot of new issues and a lot has to be learned.”

Merry said it will be interesting to see if NBN recommends people keep a spare battery in their house in the event a total replacement is required quickly.

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