Too long too quiete. Before 9/11 we were coming north bound to UK when HF selcal from our company ops. "Please contact ATC". Now we looked at each other & transmitted no answer. But "a big but" we could still hear the controller a female voice & we were positive that we had not been called. We were monitoring guard as well. So no quiet period at all. Weird.
Anyway after trying another freq given to us on guard all was well.
I still don't know what occurred but believe it was a failure to hand us over to next freq in the same FIR. & somehow the frequency was receiving another station via ducting.
So mistake on our part maybe/proberbly, but talk about coincedance having two female controllers on the same freq but the transmitters miles & miles apart. As for no one coming up on guard I havn't a clue.
Anyway since then I was very carefull even getting a chuckle from a French controller after calling after parsing out of his FIR. "XXXX, xxx123, position!". Lack of handover actually happens a lot so guess some on here will also advocate shooting the controller.