Well, she's certainly holding something to her ear, and it certainly looks like a phone. She's got her far hand up like she's trying to shield the mic from wind or external noise, too. What use would a phone *be* in 1928, though? You require a network of support devices to go with it.
I wonder if it might be some sort of hearing aid? She looks like an older lady. http://beckerexhibits.wustl.edu/did/20thcent/index.htm has some pictures of 1920s hearing aids. They note as well that period hearing aids were sensitive to heat and cold. I wonder if it's possible that she has some sort of hearing aid, and she's talking to herself to try to calibrate the thing before she arrives at her destination?