SparkFun Forums

[deelip_prusty]

Hi...
Alll

I am using EVK V3 USB board which having GM 862 Quad modem.I have issued a set of AT commands to communicate with www.google.com.But i got no carrier after some commands i issued.

Step--

AT

Return: OK

2.AT+CPIN?

Return:

+CPIN

REDDY


2.AT+CGDCONT=1,"IP","airtelgprs.com","0.0.0.0",0,0<cr>

Return: OK

3.AT#USERID="Easy GPRS"<cr>

Return: OK

4.AT#PASSWD="*****"<cr>

Return: OK

5.AT#PKTSZ=300

Return: OK

6.AT#DSTO=50

Return: OK

7.AT#SKTTO=90

Return: OK

8.AT#SKTCT=600

Return: OK

9.AT#SKTSAV

10..AT#GPRS=1<cr>

return:

+IP:127.5.123.231
OK

AT#SKTD=0,80,"www.google.com",0,0

Return:
CONNECT

Then i typed in hyperterminal-
GET/HTTP/1.1<cr><lf>then pressed Enter after that i typed Host:www.google.com<cr><lf>but this line overwrote on the firstline(GET/HT..........) which i entered just before,then typed Connection:Keep-alive<cr><lf>then samething happened,over wrote on 2nd line like first line then

<cr><lf>.After tat i waited for some while had got
Return :NO CARRIER

Also i have changed the Signal Strength by AT+CSQ,it returned 30.

Can any Suggest me where am i wrong ? Suggest me any solution

[jasonharper]

Then i typed in hyperterminal-
GET/HTTP/1.1<cr><lf>then pressed Enter

That's not a valid command for a web server. Try this:

Code: Select all

GET / HTTP/1.1

Notice the two spaces I added. The line consists of three space-separated parameters: a command (GET), a pathname (/), and a protocol (HTTP/1.1).

Also note that "<cr>" is a common abbreviation for a carriage return (Control-M), and "<lf>" stands for line feed (Control-J) - you weren't supposed to type those in literally. With many servers, you can just hit Enter instead, although that's not technically correct.

[deelip_prusty]

Hi friend...

As per ur suggestion , i tried with thi but same result ....


AT#SKTD=0,80,"www.google.com",0,0
return:
CONNECT

return:
Content-Type: text/html
Date: Mon, 27 Aug 2007 09:31:43 GMT
Connection: close
Content-Length: 20

NO CARRIER

This No Carrier displayed after 30-40 sec of entering the line GET / HTTP/1.1 as out put in hyperterminal.Nothing more than that in output.

Any other solution...

[jasonharper]

Sorry, I can't duplicate this problem when connecting to google.com via telnet (which should work just the same as via your GM862).

Are you typing the commands correctly on the first try? Keep in mind that there is no line editing once you're connected to the server. For your testing, you may want to create a text file with the GET command and any following header lines, which can be sent without having to retype it all correctly each time.

[deelip_prusty]

yes friend. i typed the lines

GET / HTTP/1.1
Host: www.telit.com
Connection: keep-alive

in a text file.After it returns CONNECT in hyperterminal i pasted these lines on to that. but after few sec it returns NO CARRIER

Same thing happens when m trying to interact with FTP server.

M using this GM862 modem in India through AIRTEL GSM network SIM which is GPRS enabled. Here airtel using frequency range 900 Mhz.

Is frequency range a issue? Airtel Help Center people are saying that they no support for this type of modem. Is this a another issue?

here am pasted the output of hyperterminal.....]

i have activated echo type character locally in the ASCII setup of hyperterminal properties and <cr> is default set.


atat
OK
atat++ccggdcdcoontnt==11,,""ipip"",,""aaiirrtetellggpprsrs.c.coomm"",,""00..00..
"0..00"
OK
atat##uussereridid==""sasarraanngg""
OK
atat##ppasasswsw==""******""
OK
atat##gpgprrss==11
+IP: 172.29.42.118

OK
atat##sskkttdd==00,,8800,,""wwwwww..ggooooggllee..ccoomm"",,00,,00
CONNECT
GET / HTTP/1.1<lf>
NO CARRIER

Any Guidlines

[maokh]

Does the header come right when it sends NO CARRIER?

This could be a DTR issue. Makes sense why you are seeing it on FTP as well.

[deelip_prusty]

Hii..
Friend..

i didnt get u.. Wat the Header u are asking abt?. How can i get it...

Would u tell me the Exact AT command for this..

About the DTR switch, it is set Low.

i want to know whether the steps am following are right or wrong ?

[maokh]

Now that I look at this more, i think you are just botching the HTTP request. You might want to take a look at RFC 2616.

[deelip_prusty]

Problem Solved abt NO Carrier


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