SIMCOMM 300DZ GPRS AT+CSTT

[movie_freak]

at+cstt

Hi,

I tried to search this but didn't found it. I am using SIM300DZ as my gprs modem.

I have the following queries:

--> how many similar modems can send data at a single instance of time on a server listening to it on a particular port number(i.e. on a single port)

--> For the same above point at the server end, what is the way to handle data coming from similar modems(more than one) at the same time, if i already have implemented it for one modem

--> I want to know whether to use the port number and server Ip, in the embedded application code to be static or variable?? (I think it should be variable:idea

--> I know that the "APN" used need to be entered by the user according to his operator, but can the username and password be left blank, if i am desiging this for many modems would it work if i leave them or is it necessary??

--> what about the DNS?? can i use static worldwide DNS like 4.2.2.2 or would there be a chance that it can also change and I need to keep it changeable??

I'll be waiting for all the valuable responses!!

please reply!!

Many Thanks,
Surya

 

[movie_freak]

at+cstt=

Guys pls reply, im sure those guys already worked or working on GPRS modem would be knowing this..

Many Thanks,
Surya

 

[pisoiu]

simcomm

Hi,

I tried to search this but didn't found it. I am using SIM300DZ as my gprs modem.

I have the following queries:

--> how many similar modems can send data at a single instance of time on a server listening to it on a particular port number(i.e. on a single port)

That depends on the server, on how many connections can accept. The destination port is the same, but the source port is different. Think about a web server, which listens on the port 80. It can accept a lot of simultaneous connections.

--> For the same above point at the server end, what is the way to handle data coming from similar modems(more than one) at the same time, if i already have implemented it for one modem

You must identify the sender somehow, usually by transmitting some form of unique data (serial number, etc.). Often, in GPRS networks, the source IP is the same even from different equipments, and the source port is random.

--> I want to know whether to use the port number and server Ip, in the embedded application code to be static or variable?? (I think it should be variable:idea

It is preferably to use URL. If you use IP, and you have to change the server location, you're in trouble.

--> I know that the "APN" used need to be entered by the user according to his operator, but can the username and password be left blank, if i am desiging this for many modems would it work if i leave them or is it necessary??

It is absolutely necessary to provide APN, user name and password, as indicated by your operator. Otherwise, the modem will not attach to GPRS context.

--> what about the DNS?? can i use static worldwide DNS like 4.2.2.2 or would there be a chance that it can also change and I need to keep it changeable??

You can use them, but if they will fail someday, or the route is broken, you're in trouble. Usually, GPRS nets provides DNS servers, but I don't know if Simcom can handle them.

I'll be waiting for all the valuable responses!!

please reply!!

Many Thanks,
Surya

 

[movie_freak]

sim300dz trouble

Thanks for pisoiu for his valuable inputs..

i got some answers, thought i should share it

--> how many similar modems can send data at a single instance of time on a server listening to it on a particular port number(i.e. on a single port)

It depends on the server, on how many connections it can accept. Also there would be a limitation on each port for a maximum number of clients that it can handle, depending on the server implementation.

--> For the same above point at the server end, what is the way to handle data coming from similar modems(more than one) at the same time, if i already have implemented it for one modem

Using a multitasking server, a new thread is created each time a client gets connected to handle it's request, hence serving multiple clients at the same time.
Though you need to distinguish between different clients with a unique number.

--> I want to know whether to use the port number and server Ip, in the embedded application code to be static or variable?? (I think it should be variable:idea

Its better to have a URL as suggested by "Pisoiu", but having serverip and portnumber variable, it gives us the advantage for easy future changes, portability and implementation

--> I know that the "APN" used need to be entered by the user according to his operator, but can the username and password be left blank, if i am desiging this for many modems would it work if i leave them or is it necessary??

It is absolutely necessary to provide APN, user name and password, as indicated by your operator. Otherwise, the modem will not attach to GPRS context.

--> what about the DNS?? can i use static worldwide DNS like 4.2.2.2 or would there be a chance that it can also change and I need to keep it changeable??

There is no need to enter DNS command in newer firmware of SIM300D

Cheers,
Surya

 

[sumansingh]

hello surya...i have small doubt regarding this APN num if i use here multiple sim cards in single modem then how i configure?

 

[movie_freak]

As you already may know the fact that APN's are different for different network operators, even can be different for same operator in different regions..

Use can use the AT+CGDCONT and AT+CSTT command in the same order on the modem to change any APN desired . If you wish to do it in an application program it can be done in many ways and it should be your task to play around these commands and make it according to your needs..


Regards,
Surya

 

[sumansingh]

hello surya ...
I am new to this GSM/GPRS programming stuff.here i am using dual sim(different operators ) in one modem.but my device gives the data to one sim at a time here i am using MUX to switchg the data means if one operator not available then it switch to another operator and send the frame to server like this. so here HOW TO CONFIGURE THE "APN" NUM TO BOTH SIM? for selection of operator v r using at+cops but wt about this APN num.....? plz help me i dnt knw wt to do..


thanx ,

suman