Yealink T48S Series - Phone Key Reference; Call Control Keys

Phone Keys
Menu.
Turns Headset Off/On.
Turns Speakerphone Off/On.
Mutes/Unmutes Speaker.
Holds/Resumes a Call
Transfers a Call.
Connects to Voicemail.
Left/Right Selects Accounts or Call Lists
Up/Down Selects Contacts or Entries
Adjusts the Volume
Confirms Actions. Answers Incoming Calls.
Cancels Actions. Rejects Incoming Calls.