If you don’t have any internet access! how you can read your e-mails?
Because Asterisk pbx is open source based on Linux platform as all developer they know one of them (Nerd Vittles) develop a nice telephony applications named MailCall .
What MailCall do?
Well, MaillCall can reads your email messages to you over the telephone. All you have to do is dial up your Asterisk server from any touchtone telephone.