Hallo, I'm doing a project (for a university exam) based on a 8051 microcontroller that comands with at commands a siemens cellular using 8051 serial port. Siemens cellular is connected to 8051 through its data cable,but: 1)if i send at commands to cellular with hyper terminal,it' ok 2)if i send at commands from micro to pc,it's ok 3)if i send at commands from micro to cellular,it doesn't responds. what can i do? thanks
connecting 8051 to cellular
Started by ●February 19, 2004
Reply by ●February 19, 20042004-02-19
On Thu, 19 Feb 2004 16:55:09 GMT, sampei wrote:>I'm doing a project (for a university exam) based on a 8051 microcontroller >that >comands with at commands a siemens cellular using 8051 serial port. >Siemens cellular is connected to 8051 through its data cable,but: >1)if i send at commands to cellular with hyper terminal,it' ok >2)if i send at commands from micro to pc,it's ok >3)if i send at commands from micro to cellular,it doesn't responds. >what can i do?I'd check the signal levels coming out of the serial port on the micro, to make sure their OK for the cellphone. Is it meant to be RS-232? If, so, you may well find that the PC will quite happily read serial data at TTL logic levels, but the cellphone is requiring "true" RS-232 levels (-10V marking , +10V spacing). Are you using a suitable level converter (Maxim MAX232 series are common for this)? -- Max
Reply by ●February 19, 20042004-02-19
sampei wrote:> Hallo, > I'm doing a project (for a university exam) based on a 8051 microcontroller > that > comands with at commands a siemens cellular using 8051 serial port. > Siemens cellular is connected to 8051 through its data cable,but: > 1)if i send at commands to cellular with hyper terminal,it' ok > 2)if i send at commands from micro to pc,it's ok > 3)if i send at commands from micro to cellular,it doesn't responds. > what can i do? > thanksIt might be the handshaking on the phone RS-232. You might need to tie some lines appropriately. I think I had to do something like this when using a Siemens M20. Leon -- Leon Heller, G1HSM Email: aqzf13@dsl.pipex.com My low-cost Philips LPC210x ARM development system: http://www.geocities.com/leon_heller/lpc2104.html
Reply by ●February 19, 20042004-02-19
"sampei" <diego.logrillo@tin.it> wrote> Hallo, > I'm doing a project (for a university exam) based on a 8051 microcontroller > that > comands with at commands a siemens cellular using 8051 serial port. > Siemens cellular is connected to 8051 through its data cable,but: > 1)if i send at commands to cellular with hyper terminal,it' ok > 2)if i send at commands from micro to pc,it's ok > 3)if i send at commands from micro to cellular,it doesn't responds. > what can i do?Have you crossed the signals over, that is Rx --> Tx and Tx --> Rx? http://www.airborn.com.au/serial/rs232.html
Reply by ●February 20, 20042004-02-20
On Thu, 19 Feb 2004 16:55:09 GMT, "sampei" <diego.logrillo@tin.it> wrote:>Hallo, >I'm doing a project (for a university exam) based on a 8051 microcontroller >that >comands with at commands a siemens cellular using 8051 serial port. >Siemens cellular is connected to 8051 through its data cable,but: >1)if i send at commands to cellular with hyper terminal,it' ok >2)if i send at commands from micro to pc,it's ok >3)if i send at commands from micro to cellular,it doesn't responds. >what can i do? >thanks >The GSM Modules often have a full modem serial implimentation. Int other words you must make sure of the CTS, DTR etc. signals as well. Regards Anton Erasmus
Reply by ●February 21, 20042004-02-21
A guy at work had the same problem. It turned out that the cellphone was echoing the incoming AT commands and he wasn't prepared to parse them. Evidently, there is some way to turn off echoing. --Anthony "sampei" <diego.logrillo@tin.it> wrote in message news:NT5Zb.258246$VW.10323324@news3.tin.it...> Hallo, > I'm doing a project (for a university exam) based on a 8051microcontroller> that > comands with at commands a siemens cellular using 8051 serial port. > Siemens cellular is connected to 8051 through its data cable,but: > 1)if i send at commands to cellular with hyper terminal,it' ok > 2)if i send at commands from micro to pc,it's ok > 3)if i send at commands from micro to cellular,it doesn't responds. > what can i do? > thanks > > >
Reply by ●February 21, 20042004-02-21
Anthony Wong wrote:> > A guy at work had the same problem. It turned out that the > cellphone was echoing the incoming AT commands and he wasn't > prepared to parse them. Evidently, there is some way to turn > off echoing.ATE1 and ATE0. Please do not toppost. -- Chuck F (cbfalconer@yahoo.com) (cbfalconer@worldnet.att.net) Available for consulting/temporary embedded and systems. <http://cbfalconer.home.att.net> USE worldnet address!
