SER_DDCD
sig, SER_DCD, SER_DDCD);
SIGCHG(bes & BES_DCD, sig, SER_DCD, SER_DDCD);
SIGCHG(bes & BES_DCD, sig, SER_DCD, SER_DDCD);
SIGCHG(bes & FLD(USR2, DCDIN), sig, SER_DCD, SER_DDCD);
SIGCHG(dummy, sig, SER_DCD, SER_DDCD);
SIGCHG(bes & BES_DCD, sig, SER_DCD, SER_DDCD);
SIGCHG(bes & BES_DCD, sig, SER_DCD, SER_DDCD);
if (sig & SER_DDCD)
SIGCHG(1, sig, SER_DCD, SER_DDCD);