From Bright Pattern Documentation
How to Send Numeric Information
When making an outbound call to a business number, you may sometimes be connected to an interactive voice application and asked to enter some numeric information. For example, you may need to enter the party’s extension or select one of the available service options.
To enter numeric information, click the Dial Pad tab 
. Click the desired digit or a combination of digits.
You can also use the numeric keys of your computer keyboard to produce numeric tones when the Dial Pad tab is selected.