IP address required by the dial-in server
Set this option if you require incoming callers on serial port ttyname to use a particular IP address. Your address space might have a limited number of IP addresses that are available for PPP in comparison to the number of potential callers. In this situation, consider assigning an IP address to each serial interface that is used for PPP on the dial-in server. This assignment implements dynamic addressing for PPP.
The asyncmap option maps control characters that cannot be received over the serial line by the particular modem or ISDN TA. When the xonxoff option is used, pppd automatically sets an asyncmap of 0xa0000.
map-value states, in hexadecimal format, the control characters that are problematic.
init "chat -U -f /etc/ppp/mychat"
Security parameters that are listed in the pppd(1m) man page