Tutorial: GSM Datacall How to Connect to GSM Modem Remotely via GSM Network for Data Call


Introduction

In many application such as datalogger and remote location (without telephony or 3G network), it is required to be able to connect to remote location using GSM Modem for remote data connection using Serial Commport or using Datalogger software (that connects to commport for setup and upload/down data etc).

It is simple and easy using GSM Modem that supports Circuit Switch or GSM Datacall.

Equipment Needed

A PC with serial comm Port (or a USB to Serial Adaptor)

A Serial Terminal Program (in this case, we had chosen to use the free Hypterminal that is present on WIN9x/WINXP)

Setting Up Hypterminal

1) Run Start -> All Program -> Accessories -> Communication -> Hypterminal

2) In a dialog Box, it ask for a connection name. Just type a description (for example T115K). Select a Comport where the COMx is the communication port that the Enfora GSM Modem is physcically conneted to.

Click OK

3) Next in the configure button, click on it to set up the comport property. Set up the COMport for 115.2Kbps, 8 Databit, No Parity, 1 stop bit and Non Flow Control (or Hardware Flow Control). Apply and Save.  Pls note that if you install a USB to serial ComPort Adaptor, typically the COMPORT will be in a different COMx Number. Make sure that you select the correct COMx Number, and also ensure the USB to Serial Port Aaptor is always connected to the same comport that you installed the driver initially.

4) Now click on the icon to connect the ComPort by using the Connect.

  

5) Now do the following on the hypterminal to experiment with the various AT command set for Data Call using GSM Network.

1). Type AT and press <ENTER> the modem should respond with OK. This will verify that you are communicating with the modem. If you cannot see characters entered on the screen, enter ATE1V1.

2). The following examples provide the AT commands and responses for setting modem parameters. For more information about the commands and response codes, see the GSM0107AT001 Enfora Enabler IIG AT Command Set.

3)  The default class of service type for the Enfora Enabler-G module is for data. The following example provides the AT commands for requesting the Enfora Enabler-G module to initiate a data call.

AT+FCLASS=0 Sets the traffic channel type to Data mode if the class of service was previously changed to Voice mode. (Data mode is the default class of service). Not required if in the default mode.

Note: This command is required only if the class of service has been changed from data mode (default) to voice mode.

OK Modem Response.

AT+CBST=7,0,1 Sets the Bearer type to: 9600 Baud, non-Transparent call.

OK Modem Response.

ATD1234567890 AT command to dial the phone number.

OK The OK response is followed by the "Connect" response when the connection is completed.

CONNECT Data call connected

+++ Change state of modem from data to command mode.

ATH Terminates the call.

4). For an incoming data call the modem can be configured to auto answer or manually answer the call. To set the modem to auto answer, set the following command:

ATS0=001 Auto answer the call on the first ring indication.

5) . To configure the modem to manually answer an incoming call, enter the following:

ATS0=000 Disable auto answer.

RING Ring indication of inbound data call.

ATA Answers inbound data call.

OK Modem Response.

CONNECT Data call successfully connected.

+++ Change state of modem from data to command mode.

ATH Terminates the call.

6)  The Enfora Enabler-G module supports the AT commands for requesting to initiate both mobile-originated (MO) and mobile-terminated (MT) voice calls.

7)  The following example provides the AT command for requesting the Enfora Enabler-G module to initiate a mobile-originated (MO) voice call. This command assumes that the Enfora Enabler-G module is configured for the Data Call mode (default).

ATD1234567890; AT command to dial the telephone number. The ";" after the number indicates that this is a voice call.

OK Modem Response.

ATH Terminates the call.

OK Modem Response.

8). The following example provides the AT command for requesting the Enfora Enabler-G module to initiate a mobile-terminated (MT) voice call. This command assumes that the Enfora Enabler-G module is configured for the Data Call mode (default).

OK

RING Displayed for incoming call notification.

ATA Command to manually answer the MT call. If "Auto

Answer" is enabled (the ATS0=x command, where x = "the number of rings") the call will be automatically answered.

OK Modem Response.

ATH Terminates the call.

OK Modem Response.

Link: Documentation and AT Command Set for Enfora GSM Modem


 

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