Thank you. Other than aesthetics they seem to be really trying to maintain a sense of realism... Phones just wouldn't be functioning with no electricity to power the infrastructure. It was the only answer.

Real question is, does he come back from it? I mean Hershel has to know he is off his rocker, when he picked up the phone there was a notable lack of dial tone and you could see the concern in his eyes.

Crazy stuff!