The cable the device came with was made to connect to a Palm?
I find this difficult to believe. More likely you have a device that
has a cable that was made to connect the device into a standard
PC serial port, and you have an adapter and are plugging that
into your Palm cradle? (If I'm wrong about any of my assumptions,
feel free to tell me to go jump in a lake...)
The RS232 protocol has two ends: DTE and DCE (Data Terminal
Equipment and Data Communications Equipment). "Straight"
cables connect a device of one type to a device of the other. An
example of a DCE would be a modem. A computer terminal (or
a PC running a terminal program) would be an example of DTE.
Now the Palm cradle plugs into the computer. Assuming the
cable is straight through, the Palm is taking a DCE role. Also
assuming that the device you are trying to talk to normally talks
to a PC, then it too is taking a DCE role. If you try to plug the
Palm cradle into your device's cable ... well, odds are that
they would both have been DB9m connectors and they wouldn't
plug in directly. If you went out and got a "gender changer" so
they could plug into one another, they would still both be DCE
devices and not talk to one another. You would have to have
a "null modem" in the mix. A "null modem" swaps a couple
of wires around so a DCE can pretend to be a DTE (or
the other way 'round).
Are you sure that your Palm and the other device are talking
to each other at all? You could always try running a terminal
emulator on the Palm before you bring your own code into
the mix. Prove the physical connection works. If it does
and your program still does not, -then- you've got a code
problem.
--
-Richard M. Hartman
[EMAIL PROTECTED]
186,000 mi/sec: not just a good idea, it's the LAW!
Charles Rezsonya wrote in message <10544@palm-dev-forum>...
>
>thanx, but the cable is one that came with the device, so its specific to
>that
>-----Original Message-----
>From: Steve Sabram <[EMAIL PROTECTED]>
>To: Palm Developer Forum <[EMAIL PROTECTED]>
>Date: Thursday, May 04, 2000 3:02 PM
>Subject: Re: Getting a responce from a serial device
>
>
>>First thing to do is make sure that your serial hardware (cables, wires,
>et. al.) is working and then start to write you code.
>>Sometimes you have the wrong cable and need a Null Modem cable instead of
a
>pass-thru considering the device you are using. To make
>>sure this works, get a regular terminal emulator application for the Palm.
>I recommend OnLine from MarkSpace (www.markspace.com).
>>This lets you make sure that the right data, if any, is coming into the
>Palm device.
>>
>>Damn! I'm recommending this device so much lately, I should be getting a
>commission. :)
>>
>>Steve
>>
>>Charles Rezsonya wrote:
>>
>>> i have opened a serial connection with a device at 9600, 8 bits per
char,
>1
>>> stop bit. probing the serial devices settings its at 9600 8n1. i
>believe
>>> that i'm sending it valid instructions because when i tell it to read a
>card
>>> it becomes armed. but the next obivious step is to receive the data
from
>>> the unit. i tried some serialmanager calls but on receiving data it
>fails
>>> (timeout) and transmits ok.
>>>
>>> can someone shed some light on this routine?
>>>
>>> --
>>> For information on using the Palm Developer Forums, or to unsubscribe,
>please see http://www.palmos.com/dev/tech/support/forums/
>>
>>
>>--
>>For information on using the Palm Developer Forums, or to unsubscribe,
>please see http://www.palmos.com/dev/tech/support/forums/
>>
>
>
>
--
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