wen i write into a serial port and read the port it returns no respnse?

[adhi]

i wrote at commands to a modem connected to rs232 but wen i read the port i just get an empty string. please help coz i dont know wat is wrong

[Dennis_Knutson]

What commands are you sending? Do you have the correct cable and are the com settings correct?

Before writing any code, check the above and use a program such as Hyperterminal to verify.

[adhi]

hi. thanx i tried wat u said. There was some improvement. But now when i wirte the AT command using VISA write on the serial port and then use VISA read, it just reads the AT command back. Is there anything specific i need to do

[Shreyas]

I suppose the same issue has been discussed in this and this forum.

Hope this helps!

[adhi]

hi dennis. i tried wat u sd. im using a property node now to read bytes at serial port. but after i read. i get the same AT command back along with an error saying that more bytes cud be present at the port. if i do not use the property node it gives a timeout error. please help

[Albert.Geven]

Hi

Getting the same command back is not unusual when the modem is in echoing mode.

The warning is simply that your read went ok but that the system may have sent extra data later, what most of the time is not so it is just a warning

[adhi]

hi. but im still not getn ne response from th modem. could u pls chck my vi to c i there r any errors in it or ne changes i can make

thanks

[Dennis_Knutson]

There's really nothing to check. You copied the basic example. I would suggest you place the VISA Configure Serial Port outside the loop. What is critical is the string that you are sending and you have not provided that. Enter the string, right click and select "Make Current Value Default", save the VI, and post that.

[adhi]

 hi every1

i wrote int he gsm modem. i get the AT command back wen i read(which is normal)but i do not get an ok or error (which i shld b gettn)do i need to use hand shaking with the modem? i have tried everything but the modem doesnt respond to any AT command 

pls help

[Dennis_Knutson]

A month ago, I asked you to do a couple of very basic things in order to help understand what might be wrong. It does not seem like you have done either test the connection with  program like Hyperterminal or provide the actual strings you are sending. Trying 'everything' is meaningless unless you provide details on what 'everything' actually is.