9 wire RS232

Started by Scott Lingerfelt December 4, 2003

Anyone,

I am trying to connect to a GSM modem model GM28 from Sony Ericsson. They
note that I require a 9 wire RS232 connection to communicate with the modem.
Am I correct in thinking that the SMS band is always on so I do not require
RTS (ready to send) pin on the modem and only run the carrier detect pin
directly to my PIC pin? I have searched the archives and found nothing on
this. Does anyone have an wiring example.

Thanks in advance,

**************************************
Scott Lingerfelt

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I wonder if they mean "db9" instead of "9 wire"? In other words, not really
9 physical connections, but a db9 connector?

Dunno what that GM28 is really going to want (check the manual). If it
needs to know DTR and RTS from your device, just tie them low (usually
active low pins). I would think that DCD would go low as soon as the modem
syncs up with the base station. Read it from the input pin to know when
"something" is ready (again, the manual should tell you.) If it were me,
I'd run all the inputs from the modem into the pic and use them
appropriately. I'd also run the appropriate outputs to the modem from the
pic.

GL - Dave

> -----Original Message-----
> From: Scott Lingerfelt [mailto:]
> Sent: Wednesday, December 03, 2003 5:31 PM
> To: Piclist
> Subject: [piclist] 9 wire RS232 >
> Anyone,
>
> I am trying to connect to a GSM modem model GM28 from Sony
> Ericsson. They note that I require a 9 wire RS232 connection
> to communicate with the modem. Am I correct in thinking that
> the SMS band is always on so I do not require RTS (ready to
> send) pin on the modem and only run the carrier detect pin
> directly to my PIC pin? I have searched the archives and
> found nothing on this. Does anyone have an wiring example.
>
> Thanks in advance,
>
> **************************************
> Scott Lingerfelt
>
> **************************************
> ---
> Outgoing mail is certified Virus Free.
> Checked by AVG anti-virus system (http://www.grisoft.com).
> Version: 6.0.545 / Virus Database: 339 - Release Date: 11/27/2003 > ------------------------ Yahoo! Groups Sponsor
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