I spent 5 days with tech support trying to solve this problem when we found Teams was not going to work for us as a phone services provider. Follow this and avoid wasting time.

Converting Yealink T56A and T58A phones from Teams OS to SIP to enable use with RingCentral

1. On the phone, tap the upper right corner to enter settings
2. Tap on Gear to obtain Device Settings (you may have to swipe up on the phone)
3. Select About
4. Prepare a spread sheet because you will need the following information for every phone to be converted:

1. Make sure the phone has the latest Firmware (Consult http://support.yealink.com/documentFront/forwardToDocumentDetailPage?documentId=261) If the Firmware is the latest, skip to Step 10. If not, download the latest firmware.
2. On the phone select Network and enter the password. Default user and password are admin and admin. You need to touch the screen to bring up keyboard.
3. Open a browser and go to the phone’s ip address. Login is admin admin
4. Go to Setting … Upgrade and on the bottom line, browse to the place where you downloaded the latest firmware.
5. Select the firmware and click Upload. The firmware will upload and the phone will re-boot.
6. Send the information from the spreadsheet developed in step 4 to Yealink, by going to their website and opening a support ticket.
   1. Go to http://support.yealink.com/ and select Ticket
   2. Fill in the blank and Create and Issue
   3. Inform Yealink that you want to convert the phone to a SIP phone for RingCentral
7. Yealink will send you MAC address specific licenses
8. To install the license, return to the phone’s browser page, Select Security … License
   1. Browse to the license which matches the phone ip Address. You may need to go to Settings .. About on the phone to get this again.
   2. Click Upload
   3. Then ReBoot the phone by going either to: 1) on the phone, to reboot (above About) and then selecting reboot and confirming, or 2) on the browser go to Settings… Upgrade….Reboot.
9. The next step is upgrading the firmware. Go to http://support.yealink.com/forward2download?path=ZIjHOJbWuW/DFrGTLnGyploAOxsQD/XzpOaqhFOhYrPixvrxLiND8SIanDGRXr9cOS8iIEJygNnWBLFIGPXGaurKXfcgwJHnjlDRXnDq86zW/3QsaYMxxb7em/8YM73N and download T58V(T56A)-58.83.0.15.rom
   1. Follow steps 6, 7, 8, 9.
10. Make sure you have the phone configuration screen open in a browser and on another screen you must be logged into the RingCentral Administration port.
11. On the RC Admin Portal go to Phone System – Phones and Devices -- User Phones and select a person to provision, when the next screen opens, select setup and provision.
12. Select Other phones Tab
13. Select phone
14. Change outbound proxy to SIP20.ringcentral.com
15. DO NOT close this page. You will need the User name, password and auth ID in the browser page.
16. Go to the browser for the phone and select Account – Register
    1. Turn on Line Active
    2. The label is the name of the person or position using the phone
    3. The display name is the name you want the phone to show on other phones
    4. Register Name is the Authorization ID from the Setup and Provisioning page in the RC admin site.
    5. User name is the User name from the Setup and Provision Page in the RC admin site.
    6. Password is the password from the Setup and Provision Page in the RC admin site.
    7. SIP Server 1 Server host is sip.ringcentral.com
    8. Enable Outbound Proxy
    9. Outbound Proxy Server 1 is sip20.ringcentral.com port 5090
    10. Press confirm and wait 30 seconds.
17. Check the phone for dial tone and ability to call out