The qualify, qualifyfreqok and qualifyfreqnotok settings are used
to determine the status availability of an IAX peer. If a peer is
consdered to be in a reachable (OK or LAGGED) state, it is
queried for availability every "qualifyfreqok" milliseconds. If it is
considered to be in an UNREACHABLE state, it is queried for
availability every "qualifyfreqnotok" milliseconds.The qualify=
setting turns the qualify system on (if the "yes" or xxx options
are used) or off (if qualify=no, which is by default). The
millisecond value of the qualify= setting specifies the maximum
response time of the availability acknowledgement before the
peer is considered to be in a "LAGGED" state.
Use an average of the last two PONG result to reduce falsely
detected LAGGED host. The default is ‘no’.
Force encryption insures no connection is established unless
both sides support encryption. By turning this option on,
encryption is automatically; turned on as well. The default is no