Set the state of the RTS line according to the parameter NewState. If NewsState is 0 the RTS signal is unset, otherwise it is set. This is only allowed, if the port don't use hardware handshaking. This means, v24OpenPort isn't called with V24_RTS_CTS. If hardware handshaking is used while calling this function, it aborts and returns V24_E_ILLPARM as error.The values returned are: V24_E_OK, V24_E_ILLHANDLE, V24_E_ILLPARM, V24_E_NOT_IMPLEMENTED.