Find the IP address for W52P by:

1.       While on the home screen, press OK

2.       Select 'Status' (the icon with a blue circle and the letter "i" in the middle) and press 'Ok'

3.       Select 'Base' and press 'Ok'

4.       The phone will then show the IP address

Now log into phone through web interface. Default username and password is ‘admin’.

Go to the Phone tab and then click on Configuration in the left-hand column. Under Local Configuration, click Export and save the configuration file. Refer below screenshot,

 yealink w52p

Open the configuration file in Notepad and add the below parameter in it.

account.1.sip_trust_ctrl=1

features.direct_ip_call_enable = 0

If you are using multiple account then add accordingly. E.g. account.2.sip_trust_ctrl=1 etc.

Now save the file and upload in to phone and restart the device.

You can verify the file by exporting again, it look like as shown in below picture.

 yealink w52p