A little brainstorming from someone just familiar with some of the =

basics, but by no means, could I claim to be anywhere near an expert.

  With a normal RS-232 port with a 9 or 25 pin connector, and only one =

port, it's common to loop back by connecting the 2 pins. If it's a =

female connector, I might unbend a paper clip and stick it in the =

connectors. Once a Tx pin is found, could that not that be used to find =

other pins, probably using a fairly high value resistor to protect the =

circuits?

Some terminal software like REALTERM allows watching some other RS-232 =

pins like CTS, DCD, etc. Use the software to create activity, and watch =

for results. Also some of the output pins like RTS, DTR can be set or =

cleared.

I would think the ground (common) pin could be determined by continuity =

to the connector screws or chassis ground, but then again it might be =

floating.

There are RS-232 analyzers that are nothing more than a DB-25 =

male/female with a red/green pair of LED's for each pin. I have to =

assume that all the LED's got to ground (probable resistor) at pin 7. =

How this would affect operation I don't know,

For DOS software, MEX (Modem Executive), and KERMIT were some of the =

popular terminal packages in those days. I think both allowed to set =

some of the control pins. Or you could set to transmit a long file for =

continuous activity.

On 3/14/2010 8:18 AM, Isaac Marino Bavaresco wrote:
> The TX pins are easy to identify with a multimeter. if there is no
> activity on the RS-232 they should be at some negative voltage between
> -6V to -12V (typically).
>
>
> Regards,
>
> Isaac
>
>
>
> Em 14/3/2010 00:36, jim escreveu:
>    =

>> All,
>>
>> I have a HUSKY FS/2 HH DOS machine.  This computer has a 25 pin male D25
>> connector at the end.
>> Within these 25 pins there are two RS232 ports.  However, I can't find t=
he
>> pinout for it.  I looked
>> on the website and downloaded the manual, but it is about 6-7 pages most=
ly
>> identifying what the controls
>> are and where they are.  Thee isn't any technical information in it.  At
>> least not the kind I'm looking
>> for.
>>
>> Anyway, if anyone has any information about the pinout of the D25 connec=
tor,
>> please let me know.
>> I have had a scope connected to the pins, but I don't see any activity. =
 It
>> worked the last time
>> I used it, but that has been some time ago.
>>
>> Hopefully someone will have some pinout info for it.
>>
>>
>> Thanks and Regards,
>>
>> Jim
>>
>>
>>      =

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>
>    =

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