Don’t override server-supplied timeouts

[bklang]

The current implementation of PromptBuilder makes a somewhat naive assumption that the provided timeout setting should apply to three different kinds of time-outs. The intent seems to apply best to the initial-timeout, or the amount of time the input should wait for the user to start signaling a response. But it’s also default-applied to max-silence and inter-digit timeouts. This is bad for callers who may take up to 4 seconds to start talking, and then have to wait up to 4 additional seconds after they stop talking for an answer. The server-supplied timeouts (LumenVox is around 800ms) should be the default, while still being possible to override them by the caller to #ask.

[benlangfeld]

So this was applied to the inter-digit-timeout because that was the behaviour of #ask in Adhearsion since a very long time ago. I'm happy to remove this for the reasons you state, but we do need to be sure that Punchblock's DTMF recognizer implements a sensible default in-line with LumenVox (do you have a reference for LumenVox/others defaults here?). In Adhearsion in the past, no timeout has always been the default, so we'd be changing this on two levels. Thoughts?

[bklang]

I've not found a LumenVox document that names their DTMF inter-digit timeout, but the MRCP specification says the default is 5 seconds.

[benlangfeld]

I'm happy to follow that default value for the inter-digit-timeout in Punchblock to fall in line with the MRCP spec.

[bklang]

@benlangfeld what else needs to be done here before this can be merged?

[benlangfeld]

Punchblock needs corresponding changes to add sensible defaults to its DTMF recognizer.