Great question and the answer is yes! If you are using a device that allows you to dial a phone number you also have the ability to enter a passcode via the touchscreen, you are able to use the Reservationless Audio Conferencing service.
We would caution you to enter the passcode digits slowly with your touchscreen. We have found that a touchscreen on a smart phone or tablet can be sensitive and it may not register every digit on the audio conferencing bridge. It will however...if you enter them nice and slowly!
Also, we have heard of instances where strange behaviour was noticed with a touchscreen and customers have told us the issue was escalated to their provider and it was the touchscreen itself on the device which had to be replaced.