hp50g: Serial port connector? - Hewlett Packard

This is a discussion on hp50g: Serial port connector? - Hewlett Packard ; I have googled through all the previous postings for this group, on serial connectivity; but: I am not completely sure about the connector needed. Is it the Sony mini-B? http://www.datapro.net/products/1597.html I seems pretty clear that an inverter needs to be ...

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Thread: hp50g: Serial port connector?

  1. hp50g: Serial port connector?

    I have googled through all the previous postings for this group, on
    serial connectivity; but:

    I am not completely sure about the connector needed.
    Is it the Sony mini-B? http://www.datapro.net/products/1597.html

    I seems pretty clear that an inverter needs to be used on the RX and
    TX lines before level shifting. Is this correct?

    Are these the proper flag settings for serial communication ?

    clear flag -33 ( Transfer by wire )
    clear flag -78 ( Transfer via serial )

    Is there a serial cable, specifically for the hp50g, available
    anywhere now?

    Thanks.

    -Dot-



  2. Re: hp50g: Serial port connector?

    > I am not completely sure about the connector needed.
    > Is it the Sony mini-B? http://www.datapro.net/products/1597.html


    Yes. There are two mini-b connectors. That one is the correct one.

    > I seems pretty clear that an inverter needs to be used on the RX and
    > TX lines before level shifting. Is this correct?


    Yes.

    > Are these the proper flag settings for serial communication ?
    >
    > clear flag -33 ( Transfer by wire )
    > clear flag -78 ( Transfer via serial )


    Yes.

    > Is there a serial cable, specifically for the hp50g, available
    > anywhere now?


    No, but samson cables will have them shortly.

    TW


  3. Re: hp50g: Serial port connector?

    > Are these the proper flag settings for serial communication ?
    >
    > clear flag -33 ( Transfer by wire )
    > clear flag -78 ( Transfer via serial )


    Oops. Posted a little too quick.

    -78 SF will do serial. CF is USB.

    TW




  4. Re: hp50g: Serial port connector?

    Thanks, Tim.

    Recently Tiwag posted a schematic using the ST3232 chip. He claims it
    works as shown, yet there is no signal inversion from the calculator
    before hitting the 232 level shifter chip. I wonder how that can be,
    given that it seems the logic is upside down from the calc?

    I would like to build that, but I'll check with Samson first.

    -Dot-
    On 8 Apr 2007 07:39:52 -0700, "TW" wrote:

    >> Are these the proper flag settings for serial communication ?
    >>
    >> clear flag -33 ( Transfer by wire )
    >> clear flag -78 ( Transfer via serial )

    >
    >Oops. Posted a little too quick.
    >
    >-78 SF will do serial. CF is USB.
    >
    >TW
    >
    >



  5. Re: hp50g: Serial port connector?

    On Sun, 08 Apr 2007 09:58:18 -0500:

    > Recently Tiwag posted a schematic using the ST3232 chip. He claims it
    > works as shown, yet there is no signal inversion from the calculator
    > before hitting the 232 level shifter chip. I wonder how that can be,
    > given that it seems the logic is upside down from the calc?


    I haven't built or tested anything, but found an article
    to help confuse everyone about this "signal inversion" thing:
    http://groups.google.com/group/comp....0d8f81c5382075

    So what's the opinion of folks who have actually built
    a working cable for HP50G? Can something definitive
    be posted for posterity to refer to?

    [r->] [OFF]

  6. Re: hp50g: Serial port connector?

    It's interesting in that Tiwag has tested his circuit in several
    different circumstances, and has no signal conditioning other than the
    level shifter. His confidence is contagious and his efforts sure seem
    like they will do the job.

    I need a serial cable to move forward on my little pet modbus HHT
    project with the hp50g, and I can't wait for Samson Cables to emerge
    with something. So I think I will try to get all the components and
    build it. I don't think I'll t use the Vbat line, though. It may be
    better to power the converter with it's own battery pack, and save the
    possibility of damaging the calculator by unintentionally shorting
    that line.


    On Sun, 08 Apr 2007 17:49:53 -0500, "John H Meyers"
    wrote:

    >On Sun, 08 Apr 2007 09:58:18 -0500:
    >
    >> Recently Tiwag posted a schematic using the ST3232 chip. He claims it
    >> works as shown, yet there is no signal inversion from the calculator
    >> before hitting the 232 level shifter chip. I wonder how that can be,
    >> given that it seems the logic is upside down from the calc?

    >
    >I haven't built or tested anything, but found an article
    >to help confuse everyone about this "signal inversion" thing:
    >http://groups.google.com/group/comp....0d8f81c5382075
    >
    >So what's the opinion of folks who have actually built
    >a working cable for HP50G? Can something definitive
    >be posted for posterity to refer to?
    >
    >[r->] [OFF]



  7. Re: hp50g: Serial port connector?

    On Apr 8, 6:49 am, dot wrote:
    > I have googled through all the previous postings for this group, on
    > serial connectivity; but:
    >
    > I am not completely sure about the connector needed.
    > Is it the Sony mini-B? http://www.datapro.net/products/1597.html
    >
    > I seems pretty clear that an inverter needs to be used on the RX and
    > TX lines before level shifting. Is this correct?
    >
    > Are these the proper flag settings for serial communication ?
    >
    > clear flag -33 ( Transfer by wire )
    > clear flag -78 ( Transfer via serial )
    >
    > Is there a serial cable, specifically for the hp50g, available
    > anywhere now?
    >
    > Thanks.
    >
    > -Dot-


    The plug on the datapro cable doesn't make a reliable connection as we
    found out from a few experiments.

    Jeff


  8. Re: hp50g: Serial port connector?

    On Apr 8, 3:49 pm, "John H Meyers" wrote:
    > On Sun, 08 Apr 2007 09:58:18 -0500:
    >
    > > Recently Tiwag posted a schematic using the ST3232 chip. He claims it
    > > works as shown, yet there is no signal inversion from the calculator
    > > before hitting the 232 level shifter chip. I wonder how that can be,
    > > given that it seems the logic is upside down from the calc?

    >
    > I haven't built or tested anything, but found an article
    > to help confuse everyone about this "signal inversion" thing:http://groups.google.com/group/comp....0d8f81c5382075
    >
    > So what's the opinion of folks who have actually built
    > a working cable for HP50G? Can something definitive
    > be posted for posterity to refer to?
    >
    > [r->] [OFF]


    We have developed a e-case with a convertor circuit in it that will be
    available in about 4 weeks. See stk4hp.com for details as they are
    available.

    Jeff


  9. Re: hp50g: Serial port connector?

    > Recently Tiwag posted a schematic using the ST3232 chip. He claims it
    > works as shown, yet there is no signal inversion from the calculator
    > before hitting the 232 level shifter chip. I wonder how that can be,
    > given that it seems the logic is upside down from the calc?


    the level-shifter ST232 does the inverting of RX and TX signals
    already.
    the given schematic was built and tested by me, and it works fine.
    the calc does use positive logic
    Logic High ===> +3V RX.calc ===> -3V on RX.RS232 line
    as specified by the IEEE RS232 standard.


    most of recent RS232 port implementations don't physically need the
    +3V and -3V signal levels, as specified by the IEEE RS232 standard,
    but they are also working with +3V and 0V (instead of -3V).

    if you want to build a simplified adapter, which works only with
    nonstandard RS232 port implementations (+3V / 0V), you only need to
    invert the RX and TX signals from the calc and connect them by a
    nullmodem cable ( RX to TX and vice versa).
    but this solution does not work reliable with all kinds of
    serial RS232 ports used for instrumentation and so on.
    therefore i decided to build and use the level-shifter solution.

    brgds, Tiwag


  10. Re: hp50g: Serial port connector?

    On 9 Apr., 03:28, dot wrote:

    > It's interesting in that Tiwag has tested his circuit in several
    > different circumstances, and has no signal conditioning other than the
    > level shifter. His confidence is contagious and his efforts sure seem
    > like they will do the job.
    >
    > I need a serial cable to move forward on my little pet modbus HHT
    > project with the hp50g


    btw.
    i'm interested in your modbus implementation for the HP50g

    brgds, Tiwag


  11. Re: hp50g: Serial port connector?

    I'll keep you posted on the progress. The target RTU is a Control
    Microsystems Scadapack device. By the way, I picked up a couple of
    different USB-A to USB mini-B cables today, and they are both
    incompatible with the calc. They are not specifically the Sony mini-B
    but I was disappointed that neither of them fit.

    I have several ST3232 chips on order through Newark Electronics, and
    they should be here tomorrow. I hope I can find a cable by then!

    -Dot-
    On 11 Apr 2007 02:15:38 -0700, "tiwag" wrote:

    >On 9 Apr., 03:28, dot wrote:
    >
    >> It's interesting in that Tiwag has tested his circuit in several
    >> different circumstances, and has no signal conditioning other than the
    >> level shifter. His confidence is contagious and his efforts sure seem
    >> like they will do the job.
    >>
    >> I need a serial cable to move forward on my little pet modbus HHT
    >> project with the hp50g

    >
    >btw.
    >i'm interested in your modbus implementation for the HP50g
    >
    >brgds, Tiwag



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