AT Command

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Lennart
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Posted by Lennart: Sat. May 1, 2010 - 11:28 AM
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Hi Freaks

Trying to communicate with SonyEricsson T68 using AT Commands.
Have studied several other projects that use AVR to send/receive SMS. Seems pretty straightforward.

For initial testing PC (Bray's Terminal) is used to send AT Commands to phone. MAX232 in between.

Anything sent from PC is immediately echoed back but PC never receive the expected "OK".
20 seconds after last AT Command is sent phone send "ERROR" to PC.

Have tested two T68 with same result so the problem should not be due to broken phone.
Obviously RS232-communication works since the phone reply.
Sending gibberish is echoed but phone don't reply with "ERROR".

I expected this first simple test sending "AT" and getting "OK" to work easy.
Most of my time yesterday was spent to searching on Internet for some explanation.
No success.
What am I missing?

Tags:

Learning and Information, General Electronics
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Bingo600
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Posted by Bingo600: Sat. May 1, 2010 - 11:52 AM
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I never played with T68 , but some with a T29 , sending & receiving SMS'es.

When the phone FSCK'ed up , and it DID ....

I had to send a BREAK , in order to establish comms again.

BREAK is TX "high for min 10 bitperiods" , i couldnt do it with the "uart" , so i disabled the uart tx function on my mega32, and set the portpin high for 500ms. Reenabled the uart tx , flushed buffers , and reset the AT-Statemachine.

There is an AT command to switch between OK or a numeric response 0/1/??.
And ATE1 turns on echo (phone echoes), ATE0 removes it ... if i remember correctly ..
I think the phone liked CR for EOL , not LF.
So a "\n" in strings should be a "\r"

/Bingo

/Bingo

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Lennart
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Posted by Lennart: Sat. May 1, 2010 - 12:00 PM
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Quote:
I think the phone liked CR for EOL , not LF.
So a "\n" in strings should be a "\r"

New day, new dawn...
I tested adding CR (actually before reading your post) and suddenly I got "OK" and other relevant replies from the phone.
Strange thing is I'm sure I've tested that yesterday too.

Anyway, GREAT RELIEF...
Thanks for your reply.

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j_jibran
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Posted by j_jibran: Sat. Dec 11, 2010 - 05:08 PM
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hello lennart!
thanks for your reply,
but my problem is still present,before t68, i used t610 which replies "OK" by just pressing ENTER after AT,but with t68 AT is echo backed,i have no idea about CR,LF and EOL.
what should i do after/before AT comand.
Thanks

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j_jibran
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Posted by j_jibran: Sat. Dec 11, 2010 - 05:08 PM
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hello lennart!
thanks for your reply,
but my problem is still present,before t68, i used t610 which replies "OK" by just pressing ENTER after AT,but with t68 AT is echo backed,i have no idea about CR,LF and EOL.
what should i do after/before AT comand.
Thanks

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Bronze Markbobgardner
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Posted by bobgardner: Sun. Dec 12, 2010 - 06:32 AM
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Try ATI.

Imagecraft compiler user

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Lennart
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Posted by Lennart: Sun. Dec 12, 2010 - 11:04 AM
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Quote:
what should i do after/before AT comand.
Nothing need to be sent before "AT"
After "AT" you send CR (0x0D).
The phone should reply "AT" and short time later "OK".

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