i Send AT commands from 8051 to a TMAS GSM modem , then i link up the Tx line to hyper termnial however the respond from the modem is the AT command i key in.
anyone can teach me on how to slove this?
That is called "Command Echo" and is perfectly normal.
You need to look in the modem's manual to find the AT command to disable echo...
hi,
the command error is turn off, just to check is i send a AT+CREG? it should reply something lik CREG=<mode>,1 how ever i only saw AT+CREG? in the hyperTerminal
i have check the RS232 interface with the osilloscope so the input and from the 8051 to rs232 to the modem is correct.
btw, the modem i am using is TMAS GSM modem model number tma-t35i.
been trying to troubleshoot for days.. but still cant find what when wrong. other then Tx Rx and Ground pin, is there another pin i need to connect?
"i Send AT commands from 8051 to a TMAS GSM modem , then i link up the Tx line to hyper termnial"
Not sure what you actually mean by that?
Is it like this:
MCU Tx Out ------------+------------> Modem Tx In | | | +------------> Hyperterminal
ie, you are using Hyperterminal to monitor what you're sending to the modem?
Or what?
If not, then please draw your setup - note that you need to use the 'pre' and '/pre' tags as described for posting source code: www.danlhenry.com/.../keil_code.png See also: http://www.keil.com/forum/tips.asp
Remember: the "TX" pin on a modem (DCE) is an Input - it supplies the data to be transmitted.
See: http://www.keil.com/forum/docs/thread10745.asp
thanks alot for your information, I actually make a mistake of Tx from the mcu to the Rx of the modem .
thanks alot, now i am able to continue the next part of my school project
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