splititng a file to give to a Mac user

Discussion in 'Computer Information' started by Toby, Nov 30, 2003.

  1. Toby

    Toby Guest

    Hi,

    I am a total dweeb when it comes to Mac. Is there a compression algorithm
    common to both win and Mac platforms that will allow me to span discs? I
    don't have a DVD burner and I have a file that I want to give to a friend
    with a Mac (OSX) that is > 1Gb. If there is a program like Winrar that Mac
    can read and will allow me to break the file into parts it would be very
    helpful. Or is there a splitter proggie that is common to both?

    TIA

    Toby
     
    Toby, Nov 30, 2003
    #1
    1. Advertising

  2. Toby

    Robert Baer Guest

    Toby wrote:
    >
    > Hi,
    >
    > I am a total dweeb when it comes to Mac. Is there a compression algorithm
    > common to both win and Mac platforms that will allow me to span discs? I
    > don't have a DVD burner and I have a file that I want to give to a friend
    > with a Mac (OSX) that is > 1Gb. If there is a program like Winrar that Mac
    > can read and will allow me to break the file into parts it would be very
    > helpful. Or is there a splitter proggie that is common to both?
    >
    > TIA
    >
    > Toby


    Ten or more floppies? Nuts.
    Use a null modem cable and Qmodem type programs.
     
    Robert Baer, Dec 1, 2003
    #2
    1. Advertising

  3. Toby

    Toby Guest

    The problem is that he's there and I'm here, so to speak. It's not so easy
    to get these machines in physical proximity.

    Toby
    "Robert Baer" <> wrote in message
    news:...
    > Toby wrote:
    > >
    > > Hi,
    > >
    > > I am a total dweeb when it comes to Mac. Is there a compression

    algorithm
    > > common to both win and Mac platforms that will allow me to span discs? I
    > > don't have a DVD burner and I have a file that I want to give to a

    friend
    > > with a Mac (OSX) that is > 1Gb. If there is a program like Winrar that

    Mac
    > > can read and will allow me to break the file into parts it would be very
    > > helpful. Or is there a splitter proggie that is common to both?
    > >
    > > TIA
    > >
    > > Toby

    >
    > Ten or more floppies? Nuts.
    > Use a null modem cable and Qmodem type programs.
     
    Toby, Dec 1, 2003
    #3
  4. Toby

    Thor Guest

    "Robert Baer" <> wrote in message
    news:...
    > Toby wrote:
    > >
    > > Hi,
    > >
    > > I am a total dweeb when it comes to Mac. Is there a compression

    algorithm
    > > common to both win and Mac platforms that will allow me to span discs? I
    > > don't have a DVD burner and I have a file that I want to give to a

    friend
    > > with a Mac (OSX) that is > 1Gb. If there is a program like Winrar that

    Mac
    > > can read and will allow me to break the file into parts it would be very
    > > helpful. Or is there a splitter proggie that is common to both?
    > >
    > > TIA
    > >
    > > Toby

    >
    > Ten or more floppies? Nuts.
    > Use a null modem cable and Qmodem type programs.


    >1GB of data to transfer, over a NULL MODEM CABLE?? You sir, are a

    masochist. ;-) That would be dog-ass slow even over a laplink parallel
    cable, but at least with that, it could be done in this lifetime.
     
    Thor, Dec 1, 2003
    #4
  5. Toby

    WebWalker Guest

    On 30 Nov 2003 05:43:05 -0600, "Toby" <> wrote:

    >Hi,
    >
    >I am a total dweeb when it comes to Mac. Is there a compression algorithm
    >common to both win and Mac platforms that will allow me to span discs? I
    >don't have a DVD burner and I have a file that I want to give to a friend
    >with a Mac (OSX) that is > 1Gb. If there is a program like Winrar that Mac
    >can read and will allow me to break the file into parts it would be very
    >helpful. Or is there a splitter proggie that is common to both?
    >


    Most probably your Mac friend is using Stuffit, try to check with
    him/her.
    You can get a trial copy of Stuffit from http://www.aladdinsys.com.

    --
    WebWalker

    PGP Key ID : 0xB3F1A279
     
    WebWalker, Dec 1, 2003
    #5
  6. Toby

    derek / nul Guest

    On Tue, 02 Dec 2003 07:55:12 +0800, WebWalker <> wrote:

    >On 30 Nov 2003 05:43:05 -0600, "Toby" <> wrote:
    >
    >>Hi,
    >>
    >>I am a total dweeb when it comes to Mac. Is there a compression algorithm
    >>common to both win and Mac platforms that will allow me to span discs? I
    >>don't have a DVD burner and I have a file that I want to give to a friend
    >>with a Mac (OSX) that is > 1Gb. If there is a program like Winrar that Mac
    >>can read and will allow me to break the file into parts it would be very
    >>helpful. Or is there a splitter proggie that is common to both?


    If you MAC friend has access to the web, put the file on a web or ftp site.
     
    derek / nul, Dec 2, 2003
    #6
  7. Toby

    Robert Baer Guest

    Thor wrote:
    >
    > "Robert Baer" <> wrote in message
    > news:...
    > > Toby wrote:
    > > >
    > > > Hi,
    > > >
    > > > I am a total dweeb when it comes to Mac. Is there a compression

    > algorithm
    > > > common to both win and Mac platforms that will allow me to span discs? I
    > > > don't have a DVD burner and I have a file that I want to give to a

    > friend
    > > > with a Mac (OSX) that is > 1Gb. If there is a program like Winrar that

    > Mac
    > > > can read and will allow me to break the file into parts it would be very
    > > > helpful. Or is there a splitter proggie that is common to both?
    > > >
    > > > TIA
    > > >
    > > > Toby

    > >
    > > Ten or more floppies? Nuts.
    > > Use a null modem cable and Qmodem type programs.

    >
    > >1GB of data to transfer, over a NULL MODEM CABLE?? You sir, are a

    > masochist. ;-) That would be dog-ass slow even over a laplink parallel
    > cable, but at least with that, it could be done in this lifetime.


    I figure it would take a little over 3 hours at 115Kbaud.
    Parallel would be a lot faster, but the Mac does not seem to have any
    programs to support that kind of data transfer.
    In any case, it is moot, in that the computers are so far apart.
    As someone suggested, using FTP and the net seems to be an option.
     
    Robert Baer, Dec 2, 2003
    #7
  8. Toby

    Thor Guest

    "Robert Baer" <> wrote in message
    news:...
    > Thor wrote:
    > >
    > > "Robert Baer" <> wrote in message
    > > news:...
    > > > Toby wrote:
    > > > >
    > > > > Hi,
    > > > >
    > > > > I am a total dweeb when it comes to Mac. Is there a compression

    > > algorithm
    > > > > common to both win and Mac platforms that will allow me to span

    discs? I
    > > > > don't have a DVD burner and I have a file that I want to give to a

    > > friend
    > > > > with a Mac (OSX) that is > 1Gb. If there is a program like Winrar

    that
    > > Mac
    > > > > can read and will allow me to break the file into parts it would be

    very
    > > > > helpful. Or is there a splitter proggie that is common to both?
    > > > >
    > > > > TIA
    > > > >
    > > > > Toby
    > > >
    > > > Ten or more floppies? Nuts.
    > > > Use a null modem cable and Qmodem type programs.

    > >
    > > >1GB of data to transfer, over a NULL MODEM CABLE?? You sir, are a

    > > masochist. ;-) That would be dog-ass slow even over a laplink parallel
    > > cable, but at least with that, it could be done in this lifetime.

    >
    > I figure it would take a little over 3 hours at 115Kbaud.


    HUH?? 3 hours??? We're talking about transferring 1 Gigabyte of data over a
    connection speed of 115,200BITS /second. 1GB works out to 8,589,934,592
    BITS. Divide that by 115,200 and you get 74,565 seconds, or 1242 minutes, or
    roughly 20-21 hours at best.


    > Parallel would be a lot faster, but the Mac does not seem to have any
    > programs to support that kind of data transfer.
    > In any case, it is moot, in that the computers are so far apart.
    > As someone suggested, using FTP and the net seems to be an option.
     
    Thor, Dec 2, 2003
    #8
  9. derek / nul wrote:
    > On Tue, 02 Dec 2003 07:55:12 +0800, WebWalker <> wrote:
    >
    >
    >>On 30 Nov 2003 05:43:05 -0600, "Toby" <> wrote:
    >>
    >>
    >>>Hi,
    >>>
    >>>I am a total dweeb when it comes to Mac. Is there a compression algorithm
    >>>common to both win and Mac platforms that will allow me to span discs? I
    >>>don't have a DVD burner and I have a file that I want to give to a friend
    >>>with a Mac (OSX) that is > 1Gb. If there is a program like Winrar that Mac
    >>>can read and will allow me to break the file into parts it would be very
    >>>helpful. Or is there a splitter proggie that is common to both?

    >
    >
    > If you MAC friend has access to the web, put the file on a web or ftp site.


    Great idea-if you have access to a web/ftp site that gives you 1GB or
    more of space. The cheapest way I've found of doing that is to set up my
    own server which is a bit of overkill for a one-time thing. (It has
    other benefits so I've been thinking about doing it for the past year.
    If I had to do something like this then maybe it would be the 'straw'
    that would finally drive me to get it done.)
     
    Calvin Crumrine, Dec 2, 2003
    #9
  10. Toby

    Robert Baer Guest

    Thor wrote:
    >
    > "Robert Baer" <> wrote in message
    > news:...
    > > Thor wrote:
    > > >
    > > > "Robert Baer" <> wrote in message
    > > > news:...
    > > > > Toby wrote:
    > > > > >
    > > > > > Hi,
    > > > > >
    > > > > > I am a total dweeb when it comes to Mac. Is there a compression
    > > > algorithm
    > > > > > common to both win and Mac platforms that will allow me to span

    > discs? I
    > > > > > don't have a DVD burner and I have a file that I want to give to a
    > > > friend
    > > > > > with a Mac (OSX) that is > 1Gb. If there is a program like Winrar

    > that
    > > > Mac
    > > > > > can read and will allow me to break the file into parts it would be

    > very
    > > > > > helpful. Or is there a splitter proggie that is common to both?
    > > > > >
    > > > > > TIA
    > > > > >
    > > > > > Toby
    > > > >
    > > > > Ten or more floppies? Nuts.
    > > > > Use a null modem cable and Qmodem type programs.
    > > >
    > > > >1GB of data to transfer, over a NULL MODEM CABLE?? You sir, are a
    > > > masochist. ;-) That would be dog-ass slow even over a laplink parallel
    > > > cable, but at least with that, it could be done in this lifetime.

    > >
    > > I figure it would take a little over 3 hours at 115Kbaud.

    >
    > HUH?? 3 hours??? We're talking about transferring 1 Gigabyte of data over a
    > connection speed of 115,200BITS /second. 1GB works out to 8,589,934,592
    > BITS. Divide that by 115,200 and you get 74,565 seconds, or 1242 minutes, or
    > roughly 20-21 hours at best.
    >
    > > Parallel would be a lot faster, but the Mac does not seem to have any
    > > programs to support that kind of data transfer.
    > > In any case, it is moot, in that the computers are so far apart.
    > > As someone suggested, using FTP and the net seems to be an option.


    Sorry, you are correct; i had foolishly thought 115K baud which is 8
    times faster.
     
    Robert Baer, Dec 3, 2003
    #10
  11. Toby

    Thor Guest


    > > > > >1GB of data to transfer, over a NULL MODEM CABLE?? You sir, are a
    > > > > masochist. ;-) That would be dog-ass slow even over a laplink

    parallel
    > > > > cable, but at least with that, it could be done in this lifetime.
    > > >
    > > > I figure it would take a little over 3 hours at 115Kbaud.

    > >
    > > HUH?? 3 hours??? We're talking about transferring 1 Gigabyte of data

    over a
    > > connection speed of 115,200BITS /second. 1GB works out to 8,589,934,592
    > > BITS. Divide that by 115,200 and you get 74,565 seconds, or 1242

    minutes, or
    > > roughly 20-21 hours at best.
    > >
    > > > Parallel would be a lot faster, but the Mac does not seem to have

    any
    > > > programs to support that kind of data transfer.
    > > > In any case, it is moot, in that the computers are so far apart.
    > > > As someone suggested, using FTP and the net seems to be an option.

    >
    > Sorry, you are correct; i had foolishly thought 115K baud which is 8
    > times faster.


    You sure? If my data transfer conversion chart is correct, 1 bit/second =
    1.25 baud. That would make 115K baud *slower* than 115Kbit. Working out the
    same formula, it would take about 25 hours at 115K baud.
     
    Thor, Dec 3, 2003
    #11
  12. Toby

    Robert Baer Guest

    Thor wrote:
    >
    > > > > > >1GB of data to transfer, over a NULL MODEM CABLE?? You sir, are a
    > > > > > masochist. ;-) That would be dog-ass slow even over a laplink

    > parallel
    > > > > > cable, but at least with that, it could be done in this lifetime.
    > > > >
    > > > > I figure it would take a little over 3 hours at 115Kbaud.
    > > >
    > > > HUH?? 3 hours??? We're talking about transferring 1 Gigabyte of data

    > over a
    > > > connection speed of 115,200BITS /second. 1GB works out to 8,589,934,592
    > > > BITS. Divide that by 115,200 and you get 74,565 seconds, or 1242

    > minutes, or
    > > > roughly 20-21 hours at best.
    > > >
    > > > > Parallel would be a lot faster, but the Mac does not seem to have

    > any
    > > > > programs to support that kind of data transfer.
    > > > > In any case, it is moot, in that the computers are so far apart.
    > > > > As someone suggested, using FTP and the net seems to be an option.

    > >
    > > Sorry, you are correct; i had foolishly thought 115K baud which is 8
    > > times faster.

    >
    > You sure? If my data transfer conversion chart is correct, 1 bit/second =
    > 1.25 baud. That would make 115K baud *slower* than 115Kbit. Working out the
    > same formula, it would take about 25 hours at 115K baud.


    Rats! Are you trying to make me *think* ?? How dare you!
    Seriously, from one of my numerous electronics dictionaries:
    "Baudot code. One comprising impulses in the time frame of five units,
    devised by J. M. Baudot for mechanical transmission of signals."
    We know that later on, the code was extended to 8 units, but the term
    "Baud rate" was kept.

    The Wordsworth Dictionary of Science & Technology gives:
    "baud. A measure of the signalling speed in digital communications
    system; the speed in bauds is the number of discrete conditions or
    signal events per second, e.g. one baud equals one bit/second in a train
    of binary signals. Since many digital systems transmit additional
    information for control and signalling, the baud rate is not necessarily
    the same as the DATA SIGNALLING RATE."
    Be advised that the emphasis shown is from the dictionary.

    So.
    Bits per second appears to be the data rate: 110 bits per second used
    in teletypes is 10 baud.
    Is that the sense you get?
     
    Robert Baer, Dec 4, 2003
    #12
  13. Toby

    Thor Guest


    > Rats! Are you trying to make me *think* ?? How dare you!
    > Seriously, from one of my numerous electronics dictionaries:
    > "Baudot code. One comprising impulses in the time frame of five units,
    > devised by J. M. Baudot for mechanical transmission of signals."
    > We know that later on, the code was extended to 8 units, but the term
    > "Baud rate" was kept.
    >
    > The Wordsworth Dictionary of Science & Technology gives:
    > "baud. A measure of the signalling speed in digital communications
    > system; the speed in bauds is the number of discrete conditions or
    > signal events per second, e.g. one baud equals one bit/second in a train
    > of binary signals. Since many digital systems transmit additional
    > information for control and signalling, the baud rate is not necessarily
    > the same as the DATA SIGNALLING RATE."
    > Be advised that the emphasis shown is from the dictionary.
    >
    > So.
    > Bits per second appears to be the data rate: 110 bits per second used
    > in teletypes is 10 baud.
    > Is that the sense you get?


    I started in computers after Baud was already considered an archaic term for
    modems, and comport speeds, and rarely used, so I never really considered
    the relative differences. I always worked from the assumption that 1 Baud
    and 1 bps were essentially the same in real-world because I knew that
    earlier modems were referred to by their baud rate, and that it was
    basically the same as their bps rate. In this case, I merely referred to my
    master conversion program (master converter) that lists practically all
    known forms of measurement of data transfer, and it stated that 1 bit/second
    = 1.25 Baud. Whether that is right or wrong, I don't see the conclusion of
    110 bps = 10 baud based on the information you quoted. The second paragraph
    you quoted states 1bps=1 Baud in a train of binary signals, and that many
    systems transmit extra data for control and signalling, but nothing specific
    is given as to how much extra data is transnmitted for purposes other than
    the actual user data. The way I would interpret the paragraph is that 1bps=1
    baud, in usable data throughput, but that the *true total* amount of data,
    including control and signalling data may be higher, but how much higher is
    something that isn't defined in the paragraph. So, I did a little reference
    digging myself, and I pulled out an A+ study guide book and it says:

    "The term "baud rate" refers to the number of discrete signal events per
    second in data transfer, not bits per second. The term "baud" has fallen out
    of usage. In the early days of 300, and 1200 baud modems, the baud rate
    equalled the bps. The term held over until 14.4Kbps modems entered the
    market, even though it was no longer technically correct to refer to the
    modem speed by it's baud rate."


    Now, I would interpret that statement to say that at least up until 14.4
    modems, it was conventional wisdom albiet not precisely accurate that 1 baud
    equalled 1bps. SO, I tried to find a more detailed explanation of what the
    differences were, and I ran across this detailed explanation from someone in
    comp.sys.apple2 .

    (quote)

    "Assuming you are talking about an asynchronous serial port (like the
    Super Serial Card or the IIc, or the IIgs running in async mode) then
    bps = baud rate.

    A synchronous serial port (e.g. IIgs serial port running in FM clocked
    HDLC mode as with LocalTalk) may have different bps and baud rate.

    In all cases, "bps" refers to the actual data throughput, including any
    framing overhead for the transmission format. For asynchronous data,
    this includes the start and stop bits (and parity, if any). For
    synchronous it includes any bit stuffing and framing characters, but
    doesn't include clocking information.

    The term "baud" refers to the maximum number of changes of state in the
    transmission line per second. A change of state might be a voltage
    change or current reversal for a DC signal, or a frequency, phase or
    amplitude change for an AC signal.

    Asynchronous serial data is transmitted using NRZ (non return to zero),
    in which the voltage (or current) changes between either of two levels
    according to whether a zero or one bit is being transmitted. There is a
    maximum of one change of state per raw data bit, hence one bit per baud,
    hence bps = baud rate.

    With FM modulation (as used by LocalTalk), there is a clock transition
    in each bit cell with the additional possibility of a data transition,
    therefore there is a maximum of two changes of state per raw data bit,
    hence half a bit per baud, hence baud rate = bps * 2. (Thus LocalTalk
    is 230400 bps or 460800 baud.) Incidentally, Ethernet is similar - it
    requires a maximum of two transitions per raw data bit, thus 10Base-T
    actually needs to be able to transmit data at 20M Baud.

    Here is a quick summary of the low end modem formats:

    V.21 or Bell 103 (300 bps) uses FSK (frequency shift keying): one bit
    per baud, thus 300 baud.

    V.23 (1200/75) is also FSK: one bit per baud, thus 1200 baud one way and
    75 baud the other way.

    V.22 or Bell 212 (1200 bps) uses DPSK (dual phase shift keying): two
    bits per baud, thus 600 baud.

    V.22bis (2400 bps) uses QAM (quadrature amplitude modulation): four bits
    per baud, thus 600 baud.

    V.32 (9600 bps) uses Trellis modulation. Not quite sure about this one,
    but I think it is six bits per baud, hence 1600 baud.

    V.32bis (14400 bps) is also Trellis, possibly with more states.

    (end quote)


    So what i gather from all of this is that the baud rate/data rate ratio is
    ever changing depending on the transmission method being used, and the
    protocols of that transmission method. Sometimes it's the same, sometimes,
    it's less, and sometimes it's more. If we follow the pattern of the various
    modem protocols, the trend is towards more bits per baud, the faster the
    protocol is. My conversion program is evidently a tad too simplistic on this
    matter, as the answer would appear to be not just one ratio, but one of
    several possibilities, based on the system of transmission being used. What
    do you think?
     
    Thor, Dec 4, 2003
    #13
  14. Toby

    Night_Seer Guest

    Thor wrote:
    >> Rats! Are you trying to make me *think* ?? How dare you!
    >> Seriously, from one of my numerous electronics dictionaries:
    >> "Baudot code. One comprising impulses in the time frame of five
    >> units, devised by J. M. Baudot for mechanical transmission of
    >> signals." We know that later on, the code was extended to 8 units,
    >> but the term "Baud rate" was kept.
    >>
    >> The Wordsworth Dictionary of Science & Technology gives:
    >> "baud. A measure of the signalling speed in digital communications
    >> system; the speed in bauds is the number of discrete conditions or
    >> signal events per second, e.g. one baud equals one bit/second in a
    >> train of binary signals. Since many digital systems transmit
    >> additional information for control and signalling, the baud rate is
    >> not necessarily the same as the DATA SIGNALLING RATE."
    >> Be advised that the emphasis shown is from the dictionary.
    >>
    >> So.
    >> Bits per second appears to be the data rate: 110 bits per second
    >> used in teletypes is 10 baud.
    >> Is that the sense you get?

    >
    > I started in computers after Baud was already considered an archaic
    > term for modems, and comport speeds, and rarely used, so I never
    > really considered the relative differences. I always worked from the
    > assumption that 1 Baud and 1 bps were essentially the same in
    > real-world because I knew that earlier modems were referred to by
    > their baud rate, and that it was basically the same as their bps
    > rate. In this case, I merely referred to my master conversion program
    > (master converter) that lists practically all known forms of
    > measurement of data transfer, and it stated that 1 bit/second = 1.25
    > Baud. Whether that is right or wrong, I don't see the conclusion of
    > 110 bps = 10 baud based on the information you quoted. The second
    > paragraph you quoted states 1bps=1 Baud in a train of binary signals,
    > and that many systems transmit extra data for control and signalling,
    > but nothing specific is given as to how much extra data is
    > transnmitted for purposes other than the actual user data. The way I
    > would interpret the paragraph is that 1bps=1 baud, in usable data
    > throughput, but that the *true total* amount of data, including
    > control and signalling data may be higher, but how much higher is
    > something that isn't defined in the paragraph. So, I did a little
    > reference digging myself, and I pulled out an A+ study guide book and
    > it says:
    >
    > "The term "baud rate" refers to the number of discrete signal events
    > per second in data transfer, not bits per second. The term "baud" has
    > fallen out of usage. In the early days of 300, and 1200 baud modems,
    > the baud rate equalled the bps. The term held over until 14.4Kbps
    > modems entered the market, even though it was no longer technically
    > correct to refer to the modem speed by it's baud rate."
    >
    >
    > Now, I would interpret that statement to say that at least up until
    > 14.4 modems, it was conventional wisdom albiet not precisely accurate
    > that 1 baud equalled 1bps. SO, I tried to find a more detailed
    > explanation of what the differences were, and I ran across this
    > detailed explanation from someone in comp.sys.apple2 .
    >
    > (quote)
    >
    > "Assuming you are talking about an asynchronous serial port (like the
    > Super Serial Card or the IIc, or the IIgs running in async mode) then
    > bps = baud rate.
    >
    > A synchronous serial port (e.g. IIgs serial port running in FM clocked
    > HDLC mode as with LocalTalk) may have different bps and baud rate.
    >
    > In all cases, "bps" refers to the actual data throughput, including
    > any framing overhead for the transmission format. For asynchronous
    > data,
    > this includes the start and stop bits (and parity, if any). For
    > synchronous it includes any bit stuffing and framing characters, but
    > doesn't include clocking information.
    >
    > The term "baud" refers to the maximum number of changes of state in
    > the transmission line per second. A change of state might be a
    > voltage
    > change or current reversal for a DC signal, or a frequency, phase or
    > amplitude change for an AC signal.
    >
    > Asynchronous serial data is transmitted using NRZ (non return to
    > zero),
    > in which the voltage (or current) changes between either of two levels
    > according to whether a zero or one bit is being transmitted. There
    > is a maximum of one change of state per raw data bit, hence one bit
    > per baud, hence bps = baud rate.
    >
    > With FM modulation (as used by LocalTalk), there is a clock transition
    > in each bit cell with the additional possibility of a data transition,
    > therefore there is a maximum of two changes of state per raw data bit,
    > hence half a bit per baud, hence baud rate = bps * 2. (Thus LocalTalk
    > is 230400 bps or 460800 baud.) Incidentally, Ethernet is similar - it
    > requires a maximum of two transitions per raw data bit, thus 10Base-T
    > actually needs to be able to transmit data at 20M Baud.
    >
    > Here is a quick summary of the low end modem formats:
    >
    > V.21 or Bell 103 (300 bps) uses FSK (frequency shift keying): one bit
    > per baud, thus 300 baud.
    >
    > V.23 (1200/75) is also FSK: one bit per baud, thus 1200 baud one way
    > and 75 baud the other way.
    >
    > V.22 or Bell 212 (1200 bps) uses DPSK (dual phase shift keying): two
    > bits per baud, thus 600 baud.
    >
    > V.22bis (2400 bps) uses QAM (quadrature amplitude modulation): four
    > bits per baud, thus 600 baud.
    >
    > V.32 (9600 bps) uses Trellis modulation. Not quite sure about this
    > one, but I think it is six bits per baud, hence 1600 baud.
    >
    > V.32bis (14400 bps) is also Trellis, possibly with more states.
    >
    > (end quote)
    >
    >
    > So what i gather from all of this is that the baud rate/data rate
    > ratio is ever changing depending on the transmission method being
    > used, and the protocols of that transmission method. Sometimes it's
    > the same, sometimes, it's less, and sometimes it's more. If we follow
    > the pattern of the various modem protocols, the trend is towards more
    > bits per baud, the faster the protocol is. My conversion program is
    > evidently a tad too simplistic on this matter, as the answer would
    > appear to be not just one ratio, but one of several possibilities,
    > based on the system of transmission being used. What do you think?


    You guys are giving me a headache.

    --
    Night_Seer
     
    Night_Seer, Dec 4, 2003
    #14
  15. Toby

    V W Wall Guest

    Robert Baer wrote:
    >
    > Thor wrote:
    > >


    > > You sure? If my data transfer conversion chart is correct, 1 bit/second =
    > > 1.25 baud. That would make 115K baud *slower* than 115Kbit. Working out the
    > > same formula, it would take about 25 hours at 115K baud.

    >
    > Rats! Are you trying to make me *think* ?? How dare you!
    > Seriously, from one of my numerous electronics dictionaries:


    Since you seem to be intersted in thinking, here's more food for thought: ;-)

    > "Baudot code. One comprising impulses in the time frame of five units,
    > devised by J. M. Baudot for mechanical transmission of signals."
    > We know that later on, the code was extended to 8 units, but the term
    > "Baud rate" was kept.


    Not only that, but most "Modem" codes used start and stop bits, giving an
    effective 10 bits/symbol.
    >
    > The Wordsworth Dictionary of Science & Technology gives:
    > "baud. A measure of the signalling speed in digital communications
    > system; the speed in bauds is the number of discrete conditions or
    > signal events per second, e.g. one baud equals one bit/second in a train
    > of binary signals. Since many digital systems transmit additional
    > information for control and signalling, the baud rate is not necessarily
    > the same as the DATA SIGNALLING RATE."
    > Be advised that the emphasis shown is from the dictionary.


    Modern modems use several "line conditions" to represent data bits. These
    include, frequency, phase and amplitude. Add to that, recundancy checking
    and data compression and the confusion grows. So the rate of a file transfer
    depends not only on line quality, transfer method but also on file content.

    For local, (short distance), transfers, line quality does not affect the
    data rate and the transfer method/bandwidth limits the rate. Data compression
    is normally not used, and error correction is built into the hardware.

    BTW, the limit on transmission speed from a "56K" modem, results only from a
    FCC limit on the amount of power that can be put into signals on domestic
    phone lines. DSL uses an "out of band" frequency range, so can trade
    bandwidth for power, but does have distance limitations because of the high
    frequencies used.

    Virg Wall
    --
    A foolish consistency is the
    hobgoblin of little minds,........
    Ralph Waldo Emerson
    (Microsoft programmer's manual.)
     
    V W Wall, Dec 4, 2003
    #15
  16. Toby

    V W Wall Guest

    Thor wrote:
    >

    <big clip to save a few bauds>

    > So what i gather from all of this is that the baud rate/data rate ratio is
    > ever changing depending on the transmission method being used, and the
    > protocols of that transmission method. Sometimes it's the same, sometimes,
    > it's less, and sometimes it's more. If we follow the pattern of the various
    > modem protocols, the trend is towards more bits per baud, the faster the
    > protocol is. My conversion program is evidently a tad too simplistic on this
    > matter, as the answer would appear to be not just one ratio, but one of
    > several possibilities, based on the system of transmission being used. What
    > do you think?


    I didn't see your reply before my reply to Robert Baer. Also forgot to
    include an aspirin for Night_Seer.

    If any one wants to do some real thinking, look up Claude Shannon's classic
    work on data transmission theory. He was the first to wrap up signal level,
    bandwidth, and channel noise into a complete mathematical model.

    Shannon was quite a guy! I had the pleasure of being a neophyte engineer at
    Bell Labs when he was there. Didn't know him too well but his wife-to-be,
    Betty Moore, worked as a math aid in the department where I worked. He
    built a computer that did simple math using Roman numeral input! He was one of
    the great ones in information theory!

    Virg Wall
     
    V W Wall, Dec 4, 2003
    #16
  17. Toby

    Robert Baer Guest

    Thor wrote:
    >
    > > Rats! Are you trying to make me *think* ?? How dare you!
    > > Seriously, from one of my numerous electronics dictionaries:
    > > "Baudot code. One comprising impulses in the time frame of five units,
    > > devised by J. M. Baudot for mechanical transmission of signals."
    > > We know that later on, the code was extended to 8 units, but the term
    > > "Baud rate" was kept.
    > >
    > > The Wordsworth Dictionary of Science & Technology gives:
    > > "baud. A measure of the signalling speed in digital communications
    > > system; the speed in bauds is the number of discrete conditions or
    > > signal events per second, e.g. one baud equals one bit/second in a train
    > > of binary signals. Since many digital systems transmit additional
    > > information for control and signalling, the baud rate is not necessarily
    > > the same as the DATA SIGNALLING RATE."
    > > Be advised that the emphasis shown is from the dictionary.
    > >
    > > So.
    > > Bits per second appears to be the data rate: 110 bits per second used
    > > in teletypes is 10 baud.
    > > Is that the sense you get?

    >
    > I started in computers after Baud was already considered an archaic term for
    > modems, and comport speeds, and rarely used, so I never really considered
    > the relative differences. I always worked from the assumption that 1 Baud
    > and 1 bps were essentially the same in real-world because I knew that
    > earlier modems were referred to by their baud rate, and that it was
    > basically the same as their bps rate. In this case, I merely referred to my
    > master conversion program (master converter) that lists practically all
    > known forms of measurement of data transfer, and it stated that 1 bit/second
    > = 1.25 Baud. Whether that is right or wrong, I don't see the conclusion of
    > 110 bps = 10 baud based on the information you quoted. The second paragraph
    > you quoted states 1bps=1 Baud in a train of binary signals, and that many
    > systems transmit extra data for control and signalling, but nothing specific
    > is given as to how much extra data is transnmitted for purposes other than
    > the actual user data. The way I would interpret the paragraph is that 1bps=1
    > baud, in usable data throughput, but that the *true total* amount of data,
    > including control and signalling data may be higher, but how much higher is
    > something that isn't defined in the paragraph. So, I did a little reference
    > digging myself, and I pulled out an A+ study guide book and it says:
    >
    > "The term "baud rate" refers to the number of discrete signal events per
    > second in data transfer, not bits per second. The term "baud" has fallen out
    > of usage. In the early days of 300, and 1200 baud modems, the baud rate
    > equalled the bps. The term held over until 14.4Kbps modems entered the
    > market, even though it was no longer technically correct to refer to the
    > modem speed by it's baud rate."
    >
    > Now, I would interpret that statement to say that at least up until 14.4
    > modems, it was conventional wisdom albiet not precisely accurate that 1 baud
    > equalled 1bps. SO, I tried to find a more detailed explanation of what the
    > differences were, and I ran across this detailed explanation from someone in
    > comp.sys.apple2 .
    >
    > (quote)
    >
    > "Assuming you are talking about an asynchronous serial port (like the
    > Super Serial Card or the IIc, or the IIgs running in async mode) then
    > bps = baud rate.
    >
    > A synchronous serial port (e.g. IIgs serial port running in FM clocked
    > HDLC mode as with LocalTalk) may have different bps and baud rate.
    >
    > In all cases, "bps" refers to the actual data throughput, including any
    > framing overhead for the transmission format. For asynchronous data,
    > this includes the start and stop bits (and parity, if any). For
    > synchronous it includes any bit stuffing and framing characters, but
    > doesn't include clocking information.
    >
    > The term "baud" refers to the maximum number of changes of state in the
    > transmission line per second. A change of state might be a voltage
    > change or current reversal for a DC signal, or a frequency, phase or
    > amplitude change for an AC signal.
    >
    > Asynchronous serial data is transmitted using NRZ (non return to zero),
    > in which the voltage (or current) changes between either of two levels
    > according to whether a zero or one bit is being transmitted. There is a
    > maximum of one change of state per raw data bit, hence one bit per baud,
    > hence bps = baud rate.
    >
    > With FM modulation (as used by LocalTalk), there is a clock transition
    > in each bit cell with the additional possibility of a data transition,
    > therefore there is a maximum of two changes of state per raw data bit,
    > hence half a bit per baud, hence baud rate = bps * 2. (Thus LocalTalk
    > is 230400 bps or 460800 baud.) Incidentally, Ethernet is similar - it
    > requires a maximum of two transitions per raw data bit, thus 10Base-T
    > actually needs to be able to transmit data at 20M Baud.
    >
    > Here is a quick summary of the low end modem formats:
    >
    > V.21 or Bell 103 (300 bps) uses FSK (frequency shift keying): one bit
    > per baud, thus 300 baud.
    >
    > V.23 (1200/75) is also FSK: one bit per baud, thus 1200 baud one way and
    > 75 baud the other way.
    >
    > V.22 or Bell 212 (1200 bps) uses DPSK (dual phase shift keying): two
    > bits per baud, thus 600 baud.
    >
    > V.22bis (2400 bps) uses QAM (quadrature amplitude modulation): four bits
    > per baud, thus 600 baud.
    >
    > V.32 (9600 bps) uses Trellis modulation. Not quite sure about this one,
    > but I think it is six bits per baud, hence 1600 baud.
    >
    > V.32bis (14400 bps) is also Trellis, possibly with more states.
    >
    > (end quote)
    >
    > So what i gather from all of this is that the baud rate/data rate ratio is
    > ever changing depending on the transmission method being used, and the
    > protocols of that transmission method. Sometimes it's the same, sometimes,
    > it's less, and sometimes it's more. If we follow the pattern of the various
    > modem protocols, the trend is towards more bits per baud, the faster the
    > protocol is. My conversion program is evidently a tad too simplistic on this
    > matter, as the answer would appear to be not just one ratio, but one of
    > several possibilities, based on the system of transmission being used. What
    > do you think?


    I think you have it nailed down.
    On the teletype and RS-232 systems, 8 bits may or may not include
    parity; one start bit and 1, 1.5 or 2 stop bits, approaching 1 stop bit
    as equipment got faster.
    Thanks for the explaination re: trellis coding.
     
    Robert Baer, Dec 5, 2003
    #17
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. lib
    Replies:
    0
    Views:
    515
  2. lib
    Replies:
    1
    Views:
    664
  3. * * * Y o u r . S h e p h e r d . A q u i l a . D

    mac!! mac!!!

    * * * Y o u r . S h e p h e r d . A q u i l a . D, Jun 2, 2005, in forum: Computer Support
    Replies:
    7
    Views:
    761
    Aquila Deus
    Jun 3, 2005
  4. l#

    GIVE ME FILM OR GIVE ME DEATH

    l#, Jul 14, 2005, in forum: DVD Video
    Replies:
    4
    Views:
    591
    Lookingglass
    Jul 14, 2005
  5. Anuj
    Replies:
    0
    Views:
    493
Loading...

Share This Page