Hello KaelYao
I actually figured it out myself. It's more of user training - familiarity functionality issue on how to use the tool. A question probably more suitable for a user forum,
Simply put I was unaware that in screen that pops for an active call, there is an Keypad Icon in the title bar that only displays a keypad if you click on.
My error was that I was using same keypad I used to dial the number.
Once in the call when I displayed that keypad and typed in responses to prompts, it was recognized I was able to successfully navigate any prompts
presented by the receiving phone system.
The problem is resolved and no further assistance is required. Thanks for reaching out.