adl_OpenDevice and getting signal state

I wanted to “force” the signal of the CTS output pin of the UART2.

I did it with the following code:

sUartSsIoc_t signal_state;	
signal_state.op = G_IOC_OP_SET;
signal_state.sig_id = UART_SIG_RTS;
signal_state.state = 0xFF;
g_Uart_if->io_control( g_Uart_handle, IOC_UART_SS, &signal_state );

Strange… Why I need to use UART_SIG_RTS sig_id instead of the UART_SIG_CTS ??