Serial port on laptop for serial communication

[romiadam]

Hi,

For I student school project, I would like establish a communication between labview and PIC micro controller via serial port. I will use only Rx, Tx (please see the attached picture). My notebook does not have serial port. There are two options:

1. Using the standard USB serial R232 adapter in to USB port

2. Using a serial adapter in to ExpressCard slot which creates native serial port

I do not know which of these to buy.

The option 1 is cheaper, but not sure  whether it will works (whether Labview will detect that serial port).

The option 2 theoretically should work (but not sure too), because the manufacturer states ("will add a serial COM port as if you had a native port on your laptop")

Which option do you recommend me. Anyone of you has tried the serial communication using the USB-Serial adapter or ExpressCard adapter on laptop?

Thanks for help.

[GerdW]

Hi romiadam,

use the cheaper USB option.

But use the somewhat better converters with FTDI chips inside!

[Yamaeda]

I've used many USB serial dongles, they generally work fine.

/Y

[RTSLVU · Accepted solution]

Well they will be the same from a LabVIEW programming aspect, as both of these devices will install a virtual serial port.

You use NI-VISA to access a serial port in LabVIEW exactly the same regardless of that serial port being a hardware RS232 serial port on 220h IRQ2  or a USB device that installs a virtual serial port. 

Also beware of cheap USB to serial converters, many of these have counterfeit Prolific chip sets in them. 

Recent Prolific drivers can detect the counterfeit chips and either not work at all or worse yet cause intermittent failures.

http://www.prolific.com.tw/US/ShowProduct.aspx?p_id=155&pcid=41

I recommend only buying FTDI USB to Serial converters from a reputable source like Digi-Key.

https://www.digikey.com/product-search/en/cable-assemblies/smart-cables/1574108?k=FTDI

Also if you look closely you can buy these USB to Serial devices with a 3.3V or 5V TTL output eliminating the need for the MAX232 in your circuit. 

[romiadam]

Thanks for advice regarding to FTDI, GerdW.

[romiadam]

Thanks for information Yamaeda

[romiadam]

RTSLVU, your answer completely cover my question. The 3.3V or 5V version is a good point to save MAX232. I do not need for this project a standard RS232 logic. Thank you too.