Grandstream ATA has no dial tone

Fix silence when you pick up the phone.

Check power, cabling and registration.

Steps

1. Check the power light is solid.Use the right adapter (5V for HT80x, 12V for HT81x).
2. Check the phone is plugged into the Phone (FXS) port, not the network port.
3. Try a different phone and cord.
4. Check Status → Port Status shows the port as registered.