Listen to the voices, they sound a lot like the 8th & 9th Doctors.
We don't know whether it was 8 or 9 in the Time War. And anyway, if it was 9, we wouldn't know when he did it. It might not be the first thing he did after he regenerated to put it in that way.
"If you are receiving this message, please help me. Send a signal to the High Council of the Time Lords on Gallifrey. I am still alive! I don't know where I am! I'm on some rock like planet!"
The Doctor knows what this signal is - but he doesn't say.