I'm able to send AT commands to GSM modem,
but i am not able interface my 8051 to GSM model.
can i get sample inerfacing code for 8051 micro controller.
deare friend, i think there is a prob with your rs232 -to TTl gateway , if you r connecting a modem with your 89s51 then u require is direct wire interface nomax232 conversion takes place...bcoz with PC it does.. do this 1.make a simple attention with 89s51. 2. interconnect an lcd to display to check incoming strings. 3. always check global interrupts priority levels. 4.Then send a at with switch if you get ok in ur lcd then this means handshaking cleared....
" if you r connecting a modem with your 89s51 then u require is direct wire interface no max232 conversion" No!! This is completely false!
If you are using a (GSM) modem then it will use a true RS232 interface and will require an RS232 transceiver (MAX232, etc)
If, however, you are using some sort of embedded GSM module, then it may just use logic-level signals. But you must check the datasheet to confirm this - some modules use non-standard logic voltage levels...!
but with a sense, i have tried several modems the person is failing to get results just bcoz he is terribly confused with null modem usart architecture. moreover i can bid that more than 70% modems are ttl compactible with 8051.. like wavecomm ok with you understandings i just want to help him out not you. best way to get knowledge is to teach somebody nor to discourage like that you have done..
first you write i think there is a prob with your rs232 -to TTl gateway , if you r connecting a modem with your 89s51 then u require is direct wire interface nomax232 conversion takes place...bcoz with PC it does..
Of course the fact that you use Stupid Monkey S*** should automatically make anyone dismiss what you write, but when you state something as an "universal truth" you may mislead someone.
then when corrected, you continue, still using Stupid Monkey S***, i can bid that more than 70% modems are ttl compactible with 8051.. so what do you actually mean besides "I have no idea whatsoever what I am babbeling about"
Most (I know of no other, but as opposed to you I do not do generalizations when I do not know) modems are made for PC use and thus will have standard RS-232 interface
Erik
Note This message was edited because of rude or abusive language.
hell! too much talk now! i illustrated the thing with my mind,if there is a prob u r nobdy to talk rubbish like this , i think u r sick i never think of a guy like you. i think the administrator is sleepy here! bad bad very bad manners
u r nobdy to talk rubbish like this , i think u r sick
Now, WHO is "talking rubbish" what else is 'u' 'r' etc English it is not
"null modem usart architecture"
Null-Modems and U(S)ARTs are completely differnt issues.
"moreover i can bid that more than 70% modems are ttl compactible" No. Again that is not correct
Again, you need to distinguish a true Modem from an embedded module: A Modem will use RS232 levels and, therefore will require and RS232 Transceiver; An embedded Module most probably will not use RS232 levels - and it may not even use standard logic levels.
Consider Wavecom, for example: Their Fastrack is a Modem and it most certainly does use RS232 levels; Their Integra is an embedded Module and it does not use RS232 levels
Remember also that an RS232 transceiver inverts the signal...
"i just want to help him out"
Giving him stuff that is blatantly wrong does not help him! In fact, connecting RS232 levels direct to an 8051's pins could well damage them!