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  1. #1
    Tym
    Guest
    Looking for some guidance here please...

    Does the GSM modem in an Ericsson R520m support v42bis data
    compression?

    I ask 'casue my Nokia 6310i doesn't and I need a GSM modem which
    does, and so am looking at an R520M to replace it with.

    Any advice welcome please


    Tym



    See More: R520M GSM Modem




  2. #2
    dummy
    Guest

    Re: R520M GSM Modem

    The ER520 manual says
    "Data Transmission, upto 28.8 on networks supporting HCSD
    With V42bis compression you can reach data transmission rates upto
    4 times higher dependent on the data type and network.
    Fax upto 9.6 kb/s, Group 3 class 1 or 2, class 2 is recommended"

    The erir520.inf file for windows shows this

    HKR, Settings, Compression_Off,, "+DS=0;"
    HKR, Settings, Compression_On,, "+DS=3,0,2048,32;"

    so it seems that it can, however I do not know if this is supported purely
    when used in windows, or whether the phone can use it itself if you
    are performing email or wap direct from the phone without using the
    phone as a modem for another device.
    T.
    you can see the 520 manual at
    http://www.sonyericsson.com/download...EN_Default.pdf





  3. #3
    matt weber
    Guest

    Re: R520M GSM Modem

    On Thu, 26 Feb 2004 10:31:07 GMT, [email protected] (Tym) wrote:

    >Looking for some guidance here please...
    >
    >Does the GSM modem in an Ericsson R520m support v42bis data
    >compression?
    >
    >I ask 'casue my Nokia 6310i doesn't and I need a GSM modem which
    >does, and so am looking at an R520M to replace it with.
    >
    >Any advice welcome please
    >
    >
    >Tym


    Not likely, because what you get with GSM isn't really a modem.
    Modem implies modulation/demodulation scheme, and that isn't what
    happens. On a GSM phone used for data, the data payload replaces the
    voice payload, so there is no analog transmission within the GSM
    network. Depending upon how it is done, you either get 9600 bps or
    14,400 bps payload per time slot.

    the phone tries to be blind to the actual protocol, is simply the
    physical layer of the connection.



  4. #4
    Tym
    Guest

    Re: R520M GSM Modem

    On Thu, 26 Feb 2004 17:24:33 -0700, matt weber <[email protected]>
    wrote:

    >Not likely, because what you get with GSM isn't really a modem.
    >Modem implies modulation/demodulation scheme, and that isn't what
    >happens. On a GSM phone used for data, the data payload replaces the
    >voice payload, so there is no analog transmission within the GSM
    >network. Depending upon how it is done, you either get 9600 bps or
    >14,400 bps payload per time slot.
    >
    >the phone tries to be blind to the actual protocol, is simply the
    >physical layer of the connection.


    I appreciate the feedback, but think it's flawed.

    I say this , because on my desk, in front of me, I have a blue box,
    which is a GSM modem - no phone. This works perfectly as a normal
    modem and supports v42bis data compression.

    This is made by ECL, but there others out there, and there is one
    which uses the sony ericsson chipset too...





  5. #5
    dummy
    Guest

    Re: R520M GSM Modem

    "Tym" <[email protected]> wrote in message
    news:[email protected]
    > On Thu, 26 Feb 2004 17:24:33 -0700, matt weber <[email protected]>
    > wrote:
    >
    > >Not likely, because what you get with GSM isn't really a modem.
    > >Modem implies modulation/demodulation scheme, and that isn't what
    > >happens. On a GSM phone used for data, the data payload replaces the
    > >voice payload, so there is no analog transmission within the GSM
    > >network. Depending upon how it is done, you either get 9600 bps or
    > >14,400 bps payload per time slot.
    > >
    > >the phone tries to be blind to the actual protocol, is simply the
    > >physical layer of the connection.

    >
    > I appreciate the feedback, but think it's flawed.
    >
    > I say this , because on my desk, in front of me, I have a blue box,
    > which is a GSM modem - no phone. This works perfectly as a normal
    > modem and supports v42bis data compression.
    >
    > This is made by ECL, but there others out there, and there is one
    > which uses the sony ericsson chipset too...
    >
    >

    I agree,
    Data compression consists of removing redundant repetitive characters
    or using a different bitstring for common sequences etc etc, and then
    transmitting it as 0's and 1's, the transmission medium does not matter
    at this point, so I still say the phone can do it, I just don't know if it
    will
    do it itself, for example, when retrieving pop mail, wap browsing.
    However, I suspect it cannot be used if you configure the connection for
    ISDN
    rather than standard dsm data, the ISDN modem at the other end will have
    to understand compression too, and I think they are vanishingly small..

    Regards,
    T.





  6. #6
    Tym
    Guest

    Re: R520M GSM Modem

    On Mon, 1 Mar 2004 19:03:04 +0000 (UTC), "dummy" <[email protected]>
    wrote:

    > Data compression consists of removing redundant repetitive characters
    >or using a different bitstring for common sequences etc etc, and then
    >transmitting it as 0's and 1's, the transmission medium does not matter
    >at this point, so I still say the phone can do it, I just don't know if it
    >will
    >do it itself, for example, when retrieving pop mail, wap browsing.
    >However, I suspect it cannot be used if you configure the connection for
    >ISDN
    >rather than standard dsm data, the ISDN modem at the other end will have
    >to understand compression too, and I think they are vanishingly small..


    It's a standard dial in connection, not ISDN.

    The problem I have is that having read the Ericsson info and the info
    on ny Nokia 6310, the Nokia should do it too - but it doesn't

    Switching on compression reporting (AT+DR=1 I think) reports +CD: NONE
    when connecting to the remote device

    Need to investigate the correct string to switch compression on..

    OH - BTW just to confuse the issue, its a 2400,7,n connection too.

    +IFC = 5,1 needs setting too



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