Can you connect a home phone adapter through a Wi-Fi extender?

Yes, if the extender supports wired clients

The extender joins your home Wi-Fi, then the phone adapter connects to it with a short Ethernet cable. To the phone adapter, that looks much like a wired network connection.

The connection layout

Internet modem → main router → Wi-Fi → extender → Ethernet cable → Ooma or other VoIP adapter → telephone.

This differs from access point mode. In access point mode, Ethernet normally carries the network into the extender from the router. Here, you want the extender to receive the network over Wi-Fi and provide it out through Ethernet.

Setup steps

1. Set up the extender and confirm a phone or laptop can browse through its Wi-Fi.
2. Place it where it still receives a strong router signal; the dead zone itself is often too far away.
3. Connect a laptop to the extender’s Ethernet port and verify internet access.
4. Replace the laptop with the home phone adapter.
5. Restart the adapter and allow several minutes for it to register.
6. Place incoming and outgoing test calls.

If it does not work

The extender is in the wrong mode

Look for an Access Point/Extender switch or mode setting. The desired mode is usually called Extender, Repeater, Bridge, or Wireless Bridge.

The signal is weak

An extender cannot create a good connection from a poor one. Move it closer to the router, even if that requires a longer Ethernet cable to the phone adapter.

The port has a different purpose

Some models use the port only as an input for access point mode. The manual—not the shape of the port—is the final answer.

Is it reliable enough?

For ordinary home calling, a solid extender link can work well. A direct Ethernet cable or properly wired mesh node is preferable when reliability is critical.

Source

NETGEAR extender setup and Ethernet connections