However, when it starts playing my audio files (the parts between the # signs are replaced before the VXML is returned from the server), it still allows a voice to interrupt. I only want a digit to be able to do that. Why isn't this working?
Since your prompts are inside the <record> tag, the application must listen for voice inputs because it is expecting to record them. Are you trying to capture a DTMF response or a recording? You cannot do both at the time.
That makes sense. I hadn't even thought of that. What I'm really trying to do is just listen for the end of someone's voicemail message after those prompts (I do something similar in another type of call, but bargein is set to false there anyway). I don't think this is going to work for me the same way because the prompts in this call are much longer and wouldn't be over by the time the voicemail beep came anyway, so the person would end up hearing the prompt on their message. I think I'll have to come up with another solution. But thanks for pointing out the problem, I was going nuts trying to figure out why that part wasn't at least doing what I wanted.