Interesting guess. Though I would think that the AVRCP protocol would be extremely specific and would preclude that simple of an error. But it's certainly worth investigating.

Other factors that might be relevant:

1. The amount of delay is variable. Could be a couple seconds, could be 30 seconds.

2. In "new" mode there is an on-screen indication on the car stereo's touch screen that gives a hint that it has something to do with the handshaking. Here's my rough description of why I think that:

When I use the car's touchscreen to play and pause, the car has two icons on the screen: A play icon and a pause icon. This is different from most user interfaces where there is a single icon that toggles between play and pause. On this car, it's two separate icons.

Its user interface tells me whether it's in play mode or pause mode by *highlighting* the corresponding icon. For instance, if I press the play icon, then when it goes into play mode, the play icon becomes highlighted. And if I press the pause icon, then when it goes into pause mode, then the pause icon becomes highlighted.

Normally that process is instantaneous. If I have my cell phone paired with the car stereo, if I press pause, then two things happen instantly: The music pauses instantly and the pause icon becomes highlighted instantly.

However, with the BC127, there is a significant delay in *both* actions: When I press the pause icon, it does *not* highlight right away. There is a pause of a few seconds before it becomes highlighted. And at the exact same instant which it *does* become highlighted, that is the same instant that the "AVRCP_PAUSE" message appears on the BC127's serial port!

In other words, there is some reason that the car stereo think that the BC127 hasn't received the pause command yet, and it doesn't update its UI until it gets confirmation back that the BC127 received the command.

So there is something going on here where the handshaking with the BC127 itself is being slow and problematic
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Tony Fabris