How to use NI-9607 additional RS-232 port?

[mtzhang]

NI-9607 has additional RS-232 port(Serial2,Serial3,Serial4,Serial5), also it has Serial1 as fixed port. Now when I use Serial1 in LV RT, it can works well,but when I use serial2/serial3/serial4/serial5, visa report the following error

VISA:  (Hex 0xBFFF0015) Timeout expired before operation completed.

it seems like that the additional RS-232 wasn't configured well, so i want to know how to use the 

9607 additional RS-232 port ?

[crossrulz]

If you are getting that error on a read, it means no data is coming from whatever device you have connected to that serial port.  The most common reasons are 1) no device connected, 2) wrong serial port settings, and 3) spendings bad commands.  Use the VISA Configure Serial Port to set the settings.  For the commands, you need to supply code and device info for what you are trying to talk with.

[mtzhang]

i think my serial port setting is right, see attachment
the serial1( which is 9607's RS-232 port ) can work with the same setting, and the error was reported when VISA writing not reading  the port serial2/serial3/serial4...serial7,which are additional serial ports of NI-9607