TCP on PDA with GPRS slow

[gulm]

Hi

I finded solution to activate GPRS connection form LabView for PDA (I used Pocket pc) with a dll call.

I have a problem: if I launch a PDA TCP server on PDA and I use a pc like a client (like example on labview) the transmission is very slow i transmit only casual number and client read and plot this number .

Is a problem of GPRS connection ??

Any suggestion?

thank you very much

best regards

elisa

[tst]

I have done PC to PDA comm in LV both in Wi-Fi and in CDMA (144 kbps), and in both cases the communication module was built into the device (no DLL used).

In general, Wi-Fi is much faster, and I did see a clear performance degradation when using the cellular network, but it was still fairly OK - I transmitted probably a few KB of data each time and they got to the other side after 1-5 seconds (I think it was around 1-2 secs). I also transmitted a few dozen KB, and it also went through in a few seconds. If your GPRS connection is slow, there is probably nothing you can do about it (other than switch to a faster connection).

[gulm]

Hi

thank's for the response.

I used dll only for establish connection GPRS but I used natives TCP of Labview for communication.

I watched I have the problem if I used PDA like a server but if I use Pda like a client the trasmission is faster  . Pda is connected by GPRS  but pc is in a LAN with dhcp maybe is a cause?

thank's

elisa

[tst]

When you say you used the PDA as a server, do you mean that you used the listen VI on the PDA side?
That sounds like a weird implementation because normally you would expect the server to be on all the time and listening, and the PDA is not on all the time. I presume you're doing this because of the DHCP use. Incidentally, does the PDA have a fixed IP address?

I don't think the use of DHCP should slow you down because once you get an IP address, I think it should work OK.

Maybe there is a bug in the PDA module where using the PDA as a server slows it down. You can probably simulate this by physically connecting the PDA to a computer in your network and see if it's still slow.

[gulm]

Hi, unfortunally PDA server is required by the client for his project and I verifies the time of transmissionif I transmit 150 bite 2 seconds just 4 seconds for 911 bytes transmit.

DHCP assign an unique IP it's ok but maybe the problem is time to upload for gprs protocol....

elisa

[monlas]

Hi,

I have to activate GPRS connection from LabView for PDA, please how did you do?

What kind of dll did you use?

I found a CMHELPER.dll that shoud have connection manager functions, but I 'm not able to call it from "Call Library Function Node" because I'm not able to create the stub dll.

Please, could help me?

Monica

[gulm]

Hi
You must create an ad hoc dll with system call to open and close connection...system call

best regards
elisa

[monlas]

Hi Elisa,

Thank's for your answer. The problem is that I'm not able to create dll in Visual C++. Please, could you send me (monyka_la@yahoo.it)   your code?I will be very pleasant if I could help you about something else....

Monica

[rolfk]

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@gulm wrote:

Hi

I finded solution to activate GPRS connection form LabView for PDA (I used Pocket pc) with a dll call.

I have a problem: if I launch a PDA TCP server on PDA and I use a pc like a client (like example on labview) the transmission is very slow i transmit only casual number and client read and plot this number .

Is a problem of GPRS connection ??

---

What type of GPRS link do you have? The usual speed is 14.4 kB unless you have some newer UMTS systems, so I would expect the data transmission to be VERY slow in comparison to a normal network connection.

Rolf Kalbermatter