BES_SYNC
SIGCHG(bes & BES_SYNC, sig, SER_DSR, SER_DDSR);
SIGCHG(bes & BES_SYNC, sig, SER_DSR, SER_DDSR);
SIGCHG(bes & BES_SYNC, sig, SER_DSR, SER_DDSR);
SIGCHG(bes & BES_SYNC, sig, SER_DSR, SER_DDSR);