Why data call dosn't complet????

[basemgergawy]

data call atd no carrier

i am useing GSM mobile phone sony-ericsson W800 and connect it to my PC.

i establish a call using ATD command

when i use the voice call command ATDxxxxxxxxxxx; "with semicolon" the call is established correctly but when i remove the semicolon to start data call i have the responce "NO CARRIER"

what is the error?????

is the data call needs activation from the operator ???????

 

[pisoiu]

dcd csd connection

Definetely. If your GSM operator does not activate for you the CSD option, you will not be able to perform data calls. Same for GPRS.

/pisoiu

 

[basemgergawy]

Many thanks pisoiu

but what dose CSD means????

and assuming thet the CSD is activated, do i have to configure any parameter in the phone or use any commands before ATD??

My final question.... if i connected correctly and get the responce <connected>, how i can send a packet of data "i.e. byte" to the another phone????


Thank you againg

 

[pisoiu]

The CSD connection is like a connection between landline modems. For example, you can dial from the GSM phone at a phone number where a landline modem is listening, and if you answer with it, the connection will establish. After the connection is established, your GSM modem will most likely will respond with "CONNECT" message (or its numerical equivalent), then you can perform data transfers through the serial port. You can monitor the hardware signals to view the state of the connection (ex. DCD line will signal when your connection is active if this option is configured properly with AT commands - look at the modem's datasheet) and it is advisable to use flow control during the transfers, in order to avoid data loss due to the connection performance. Most likely, when your connection is dropped, you will receive a message on the serial port, and the DCD line will become inactive. The transfers through this method are raw transfers, no packet receive method is implemented, no acknowlergements over data transfer, no nothing.
As far as I know (but I am not 100% sure), there are no special parameters which must be set in order to make CSD connections, but the option must be activated by your GSM provider.
If you want to make reliable data transfers, it is advisable to use GPRS transfers, almost all GSM modems are GPRS capable. Also, the CSD data calls are taxed per minute, but GPRS connections are taxed per quantity of information transferred.

/pisoiu