extern void net_close (struct serial *scb);
extern int net_read_prim (struct serial *scb, size_t count);
extern int net_write_prim (struct serial *scb, const void *buf, size_t count);
extern void net_close (struct serial *scb);
extern int net_read_prim (struct serial *scb, size_t count);
extern int net_write_prim (struct serial *scb, const void *buf, size_t count);