2026-11-13

Power Supply Requirements for ONT, ONU and CPE

Power AdapterNetworkCPE

Every fiber drop ends in a powered box. ONT/ONU and CPE typically run on 12V with modest current, but WiFi6 and PoE variants draw more - and the cabinet should ride through a short outage.

Typical Rails

A basic ONT/ONU runs on 12V at 0.5-1A. A WiFi6 gateway with more radios draws 1-1.5A. Spec the adapter with headroom, not the bare rating.

PoE for ONU

Some ONU units are powered by PoE (802.3af/at) from the upstream switch, removing the local adapter - handy when the switch has central UPS backup.

Redundancy at the Cabinet

For a street cabinet or building entry, put the CPE adapter on a small UPS or a shared 12V bus so a grid blink does not drop the subscriber session.

Field Reality

A Russian Smart-Terminal operator recently specified 'power supplies for subscriber equipment' - exactly this class: 12V adapters and small PoE injectors for thousands of CPE. XGW supplies both; see the IoT and network equipment power page.

Can I power an ONU from a USB port?

Only low-power ones; most need the rated 12V adapter. Check the label before substituting.

Is PoE or local adapter better?

PoE wins where the switch is UPS-backed; a local adapter wins where the switch is not, since the adapter stays up through a switch reboot.