This guide will show you how to connect a Yealink cordless phone to a Yealink T5 series desk phone. This will allow you to make and receive calls on your cordless phone as an extension of your desk phone. You will need a Yealink T5 series desk phone, a Yealink cordless phone, and a Yealink USB dongle.

The steps in this guide are based on the assumption that you have a Yealink T5 series desk phone with a USB port. If your desk phone does not have a USB port, you will need to purchase a USB dongle.

1. Plug in the USB dongle. Plug the USB dongle into the USB port on the back of the desk phone.
   
   
2. Register the cordless phone.
   
   
   • On the desk phone, click on the menu button.
     
   • Select "Deck Setup". If you do not see the "Deck Setup" icon, that means that the desk phone is not recognizing the USB dongle. 
   • Once you have selected "Deck Setup", you will see a list of handsets.
   • Select the cordless phone that you want to register.
   • Click on the "Start Registration" button.
   • On the cordless phone, click on the "Register" button.
   • The desk phone and the cordless phone will search for each other.
   • Once they have found each other, the desk phone will display a message saying that the pairing was successful.
     
     
3. Make the cordless phone ring when the desk phone rings
   
   
   • On the desk phone, click on the back button.
   • Scroll down to "Select Slave" and select it.
   • Make sure that the "Select handset" option is set to "Handset 1".
   • Click on the "Save" button.
   • The cordless phone will now ring when the desk phone rings.

Troubleshooting:

• If the desk phone is not recognizing the USB dongle, try plugging it into a different USB port.
• If the cordless phone is not registering, make sure that it is in pairing mode. To put the cordless phone in pairing mode, you will need to press and hold the register button for a few seconds.
• If the cordless phone is not ringing when the desk phone rings, make sure that the "Select Slave" option is set to "Handset 1".