The Recall (R) button is different from the redial button. It enables you to use some of your business landline phone’s features. You can use it to give you a second dial tone – for example, when using 3-way calling.
If you don’t hear a second dial tone when you press R, make sure your phone’s selector switch (if it has one) is set to Timed, Timed Break Recall or simply ‘T’.
Check the Vodafone Business Phone User Guide [PDF: 387KB] for more information.