Aug 30, 2011

Data Frame and Rate in GSM Modem with PLC

In our earlier posts we have discussed about the how to send SMS through GSM Modem and the most used AT Commands in GSM Modem while interfacing it with PLC. Today, we will see one of important task i.e how we can set the string that is received and sent by GSM Modem. We will discuss this in detail and also see that how can we know the existing Frame and how can we change it.



Data Frame and Rate in GSM Modem with PLC


How to See Character Frame/Data Rate in GSM Modem Communication with PLC



First of all, let us see that how can we see the "Data Rate" at which our GSM Modem is communicating. For this, we have to write the AT Command in the AT command window.


AT+IPR?

This command will give the current data rate at which our GSM Modem is communicating. Now if we want to change the data rate then we can issue an AT command for the same and the data rate will be changed.

AT+IPR=<rate>

This AT Command will change the Data Rate to the New one specified in this Command and OK response will come from Modem Side.


But we have to make a note here that the Data Rate are manufacturer specific, so we have to keep in mind the Higher Limit while setting the Data Rate.


How to See/Change Data Frame in GSM Modem Communication with PLC



If we want to know that what Data frame our GSM Modem accepts and sends i.e Data Bits Stop Bits and Parity then we can easily know that by an AT command.

AT+ICF?

This AT Command we have to issue to the GSM Modem. The response from Modem will be like - +ICF: [,]. There is specific Number for each format and parity defined in GSM Modem.

You can see the Below table for this.

FORMAT---------------------MEANING
1------------------------------- 8 Data 2 Stop
2------------------------------- 8 Data 1 Parity 1 Stop
3------------------------------- 8 Data 1 Stop
4------------------------------- 7 Data 2 Stop
5------------------------------- 7 Data 1 Parity 1 Stop
6------------------------------- 7 Data 1 Stop

For Parity Refer Below Table:-

FORMAT---------------------MEANING
0-------------------------------- Odd
1------------------------------- Even
2-------------------------------Mark
3------------------------------ Space

So from the response of the GSM Modem, you can get to know that which DATA frame it is using currently. Also, if you want to change the current data frame then, we can do it easily by this AT Command.

AT+ICF=[<format>[,<parity>]]

For example, if we issue an AT command AT=[<1>[,<0>]] then the DATA Frame will be 8,2,Odd i.e 8 Data Bits, 2 Stop Bits and Odd Parity.

So we today learned about the Data Rate and Data Frame in GSM Modem while Interfacing it with PLC. We will discuss in further articles more about the GSM Modem Communication with PLC, till then you can subscribe to get all latest Updates.

If you face any problem feel free to write in comment section.

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