This attribute indicates whether inband or outband break control
conversions are being performed. If outband break control is on,
when the modem detects a break condition coming from the PSTN,
the Modem Application Layer (MAL) converts the instruction into a
primitive and forwards it to the Data Service Control (DSC). In the
opposite direction with outband break control on, when the MAL
receives a primitive from the DSC, the MAL converts the primitive
into a break and forwards it to the PSTN. When a break condition is
discovered all subsequent incoming data is discarded until a start bit
is received.