For many older legacy home phone services, such as copper and CAN Radio/HCRC, the voice service could continue to operate without power at the premises when used with a suitable non-powered handset. Newer USO voice technologies, including Telstra 4G Fixed Wireless Voice and Telstra Satellite Voice (powered by Starlink), require electricity at your premises to operate.
If the equipment required to provide your voice service loses power, your home phone will not work, including for calls to Triple Zero (000).
Power Considerations
Mains-powered premises: consider how long you need your home phone to remain operational during a power outage.
Off-grid premises: if you need your home phone available 24/7, the voice service equipment requires continuous power and becomes part of your property’s everyday electrical load. Factor this into your solar, battery and/or generator capacity, including overnight and during poor solar conditions, and consider a backup power source in case your primary off-grid power system fails.
Phone Handsets
☎️ Keep a non-powered corded phone available.
Cordless phones generally rely on a powered base station and may not work during a power outage, even if your communications equipment has backup power. Non-powered corded phones are available from Telstra – here, and other electronics retailers, such as Harvey Norman, Officeworks, JB Hi-Fi etc.
NB: A non-powered phone does not replace the need for backup power for your Telstra Smart Modem, Starlink equipment or other equipment required to operate your voice service.
Power Requirements for Current USO Voice Technologies
Watts (W) = how much power your equipment is using at a given time.
Watt-hours (Wh) = how much energy is used over time, or how much energy a battery can store. As a rough guide: runtime ≈ usable Wh ÷ watts used.
Example: If equipment uses 100 W to operate continuously, it will use approximately 100 Wh in 1 hour, 600 Wh in 6 hours or 2,400 Wh (2.4 kWh) in 24 hours.
A battery’s advertised capacity is not the same as the amount of energy that will necessarily be available to your equipment. Some energy is lost through the battery, inverter, power conversion, cables and power supplies, and actual equipment consumption can vary. For planning purposes, BIRRR allows approximately 20% for these losses when estimating backup power runtimes. Actual runtime will vary depending on equipment, battery capacity and condition, inverter/UPS efficiency, temperature and other connected loads.
If you use your backup power to run other equipment, such as a computer, monitor, cordless phone base or other devices, the available runtime for your home phone service will be reduced.
* BIRRR has used 10–15 W for 4G Fixed Wireless Voice and 85–115 W for Satellite Voice. Starlink publishes average power consumption of 75–100 W for its Standard system alone; adding Telstra’s indicative 10–15 W Smart Modem consumption gives an estimated combined Satellite Voice draw of 85–115 W, rather than Telstra’s published 65–90 W combined figure.
BackUp Power Solutions
The best solution depends on your home phone technology, how long you need backup power, whether your premises is mains-powered or off-grid, your budget and how the backup will be recharged or refuelled.
Costs and estimated runtimes are broad guides only and will vary depending on capacity, equipment, brand, installation and operating conditions.
⚠️ Backup power only protects against loss of power at your premises. 4G Fixed Wireless Voice still relies on the Telstra mobile network, while Telstra Satellite Voice relies on the Starlink network. Network outages, equipment failures, severe weather or other disruptions may still affect your home phone even when your premises has power.
➡️ Telstra – Power and Home Phone Services Fact Sheet – Telstra’s information on power requirements and indicative backup power solutions for 4G Fixed Wireless Voice and Satellite Voice.
Choosing Backup Power
When comparing a UPS or portable power station, check the capacity (Wh), output, voltage, outlets, automatic switchover (if required), recharge time and equipment compatibility. Some UPS units also provide surge protection, which may provide additional protection for connected equipment.
Telstra recommends choosing a backup power solution with pure sine wave output. Pure sine wave power closely replicates the smooth, consistent electricity supplied by the mains grid and is generally better suited to sensitive electronic and communications equipment. When purchasing backup power, check the manufacturer’s specifications and follow the power requirements for your equipment.
Consider how your backup power will be recharged during an extended outage. Depending on the product, this may be from mains power, a generator, vehicle or compatible solar panels.
For 4G Fixed Wireless Voice, backup power must be capable of powering the Telstra Smart modem. A smaller UPS designed for modems and networking equipment may be suitable for short power outages or to keep your home phone operating while you start or switch to a generator.
For Satellite Voice, backup power must be capable of powering all equipment required for the service, including the Starlink antenna/router and Telstra Smart Modem, for your required backup period. A small UPS alone will not keep the complete Satellite Voice service operating.
For larger backup systems or off-grid properties, consider seeking advice from a suitably qualified electrical or solar professional.
Where to Purchase Backup Power
Shop local where possible. Local electrical, electronics, battery and solar suppliers may be able to help with compatibility, sizing, warranty and ongoing support. Backup power solutions are also available through Australian retailers such as Jaycar, Bunnings and Officeworks, specialist UPS/battery suppliers, manufacturers including APC/Schneider Electric, BLUETTI and EcoFlow, and online retailers.
Click on the image below to see some examples of backup power solutions:
† Some portable power stations have only one AC outlet. Where multiple devices need to be powered, a suitable powerboard may be used, provided the combined load is within the ratings of the power station and powerboard. Always follow the manufacturer’s instructions.
*Estimated runtimes are based on the BIRRR power consumption and energy-loss assumptions outlined above.
NB: Products and suppliers are examples only and are not endorsed by BIRRR. Prices, specifications and availability change. Always check compatibility and ensure the product provides sufficient capacity (Wh), output and runtime for your needs.
Maintaining your Backup Power
Follow the manufacturer’s recommendations for installation, operation, testing, maintenance and battery replacement. Battery life varies considerably depending on the battery technology, age, temperature and how frequently it is discharged.
For traditional Uninterruptible Power Supply (UPS) units using lead-acid batteries, batteries commonly require replacement after around 3–5 years. The UPS itself may also need replacement as it ages. Lithium portable power stations have different expected lifespans and maintenance requirements, so always follow the manufacturer’s recommendations for your particular equipment. Test your backup power periodically to make sure it will operate your home phone equipment when you need it.
Disclaimer: This information was prepared by Better Internet for Rural, Regional & Remote Australia (BIRRR) and updated in August 2026 as a general consumer information resource. Power consumption, battery capacity and runtime figures are indicative estimates only and actual results will vary depending on equipment, configuration, battery condition, efficiency, environmental conditions and other loads. Product examples are provided for information only and are not endorsed by BIRRR. Information, prices and product specifications may change. BIRRR recommends confirming current information with your service provider, equipment supplier or a suitably qualified electrical or solar professional. This information is general in nature and does not constitute electrical or technical advice.