A string of up to 48 characters used to configured a modem
connected to the RS-232 port. Specify this string if the
modem is not Hayes compatible. Only the initialization
commands need to be specified (i.e., do not specify any
modem prefix string such as the AT attention sequence, or
any suffix such as the CR character). This string takes
effect after every line hang-up.
Default value: string of length 0.