[Tfug] Tiny "serial console"

[Harry McGregor]

Hi,

The big problem is a lot of USB "rs232" adapters don't use proper voltage.

They try and get away with +/- 5 volt instead of +/- 12 volt, and some
really crappy ones try and do +5 volt and 0 volt, instead of going negative.

You can find some USB serial adapters that have a DC/DC converter in
them that do the full +/- 12 volt

If you want a relatively small laptop with a true RS232 port, look at a
toughbook CF-19, you can find some on ebay in the <$200 range.

-Harry

On 2/16/14 11:18 AM, Bexley Hall wrote:
> Hi Robert,
>
> On 2/16/2014 8:26 AM, Robert Hunter wrote:
>> On Sun, Feb 16, 2014 at 12:34 AM, Bexley Hall<bexley401 at yahoo.com> 
>> wrote:
>>
>>> Does anyone make a "netbook" type device *with* a genuine
>>> serial port?  (USB serial ports tend not to be 100.00%
>>> compatible with *real* serial ports)
>>
>> Have you looked at those USB-to-Serial dongle thingies?
>
> Yes.  The problem is they tend not to implement "real"
> serial ports.
>
> I.e., if you are just pushing characters in/out through the
> device, it probably will suffice.
>
> But, if the serial port is intended to interface to something
> other than a "generic serial port", the adapters fall down in
> different (vendor specific) ways.
>
> Many of the devices that I attach to a serial port exploit
> particular characteristics of a "real" serial port in order
> to achieve some particular functionality.  E.g., they may
> use the modem control signals in non-generic ways and/or
> rely on specific timing relationships between when the
> software driving the serial port initiates some action and
> when it expects the "pins" to reflect that action (for example,
> controlling the "direction" of an external bi-directional
> transceiver).
>
> The same sorts of "problems" apply to USB-parallel port
> adapters.
>
> I was hoping to find a *small* laptop/netbook that would have
> at least the serial port (preferably serial AND parallel but
> the parallel port tends to be physically large).  The laptops
> that I have with these capabilities are either large/bulky
> *or* small -- but requiring external "docks/port expanders".
>
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