Yealink T48G-SKYPE FOR BUSINESS EDITION User Manual page 154

User Guide for the T48G Skype for Business phone
The touch screen is shown as below:
Configuring Simultaneously Ring on Skype for Business Client
To ring other phones simultaneously when your phone is ringing:
In Skype for Business client, click
1.
Mark the radio box of the Simultaneously ring field.
2.
Depending on your selection:
a) If you select New Number:
140
and then click Call Forwarding Settings.