This attribute specifies the line signals required to indicate that the
external equipment is in a good state (that is, data transfer can
proceed). Note that both DTE and DCE signals are specified in this
attribute. The appropriate set of specified signals will be turned on
or checked according to the actualLinkMode. The value of this
attribute must be a superset of that of the readyLineState attribute.
See also linkMode.
Description of bits:
rfs(0)
dsr(1)
dcd(2)
rts(3)