Unable to receive calls via Telephony service with TP-Link Telephony modem router

Phenomenon

The telephony has been registered successfully via TP-Link modem router, but you may get trouble to receive calls even though you can call out. The problem occurs sporadically or always. This article will guide you to do troubleshooting if you meet this situation.

Troubleshooting

Note:

Take the actions described here one at a time. After each action, check to see if the problem is resolved.

Make sure telephony is registered properly

Log into the web interface of the modem router, click Advanced-Telephony, and check if the telephony is registered with green check symbol.

How to log into the web-based interface of the AC VDSL/ADSL Modem Router

If not, check this FAQ.

Upgrade the firmware of the modem router

Refer to the FAQ to update your modem router to the latest firmware.

Turn off SIP ALG

In the user interface of the modem router, click Advanced > NAT Forwarding > Uncheck "Enable SIP ALG" > click on Save.

Disabling DND, Call Blocks, and Call forwarding

In the user interface of the modem router, click Advanced >Telephony> DND & Call Blocking, turn off DND and delete all entries of Call Blocks.

Click Advanced >Telephony>Call forwarding, and delete all entries of Call forwarding.

Deactivate "Eco DECT" and “Reduce DECT field Strength

In the user interface of the modem router, click Advanced >Telephony>DECT, uncheck "Eco DECT" and “Reduce DECT field Strength.

Maintain an Internet connection at all times

Calls to your Internet number reach the Telephony modem only when connected to the Internet. Make sure that the modem always connects to the internet.

Set up the Telephony on another modem router

To eliminate the problem, you can set up the same telephony settings on another modem router to do comparison test.

If another modem router encounters the same problem, contact your provider and have the phone number and credentials checked, also check the settings on your phone.

If the above steps can’t fix the problem, please contact TP-Link technical support team and provide us the following information.

Model number, hardware version and firmware version of your TP-Link device;

How to find the hardware and firmware version of my TP-Link device

Your internet and telephony service provider;
The model number of your DECT phone;
The result of each above troubleshooting steps.