Adjusting the volume on a Yealink T19P

Volume key - 

Ringer Volume

While the phone is displaying the Idle screen, you can use the volume key (shown above)  to adjust the ringer volume.   You will see the volume display appear on your LCD screen. 

Please note that if the ringer volume is adjusted to the minimum you will see a speaker icon with an X next to it on your LCD screen to confirm the ringer volume has been muted.  

Call Volume

To adjust the call volume you need to press the volume key during a call. This would also alter the volume of the speakerphone or your headset if you are using one when you are on the call.  You will see the volume display appear on your LCD screen.