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Poqet PC Mailing List Digest
Volume 001, Number 133, 8 Jul 1997

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  1. Text editor by Michel Huynh <Huynh@xxxxxxxx>
  2. New Web Site Hardware by Bryan Mason <bmason@xxxxxxxx>
  3. Re: Serial Port Alternatives by Bryan Mason <bmason@xxxxxxxx>
  4. Fabricating Serial Connector by faethor@xxxxxxxx (J. Lawrence)

Digest Articles

Text editor by Michel Huynh <Huynh@xxxxxxxx>


From: Michel Huynh <Huynh@xxxxxxxx>
Subject: Text editor
Date: Mon, 07 Jul 1997 11:31:48 +0200
MIME-Version: 1.0
Content-Type: text/plain
Content-Transfer-Encoding: 8bit
Content-Disposition: inline

Hi everybody !
I found a very interesting text editor on Simtel. It names FRED and his
totally free. However it runs sometimes erratically, it is very interesting
due to his large type it uses. I just wrote to his autor and hope he will
send me a recent version... while if someone want to test it, it is located
on : http://pub.vse.cz/simtel.net/msdos/editor.html and the file's name is
FRED.ZIP


New Web Site Hardware by Bryan Mason <bmason@xxxxxxxx>


From: Bryan Mason <bmason@xxxxxxxx>
Subject: New Web Site Hardware
Date: Sun, 06 Jul 1997 19:19:43 -0700
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"

Hi all!

The ISP that hosts the Poqet PC Web Site just changed over to some new
hardware.  I've gone though the Web Site, and nothing looks broken, but if
any of you spend some time over there and see something that's broken,
please let me know as soon as you can, so I can fix it.

Thanks in advance for your help.

-- Bryan


Re: Serial Port Alternatives by Bryan Mason <bmason@xxxxxxxx>


From: Bryan Mason <bmason@xxxxxxxx>
Subject: Re: Serial Port Alternatives
Date: Sun, 06 Jul 1997 19:15:50 -0700
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"

If you buy the PCMCIA serial port card, make sure that you get a money-back
guarantee.  I don't think it's going to work with the Poqet, for the same
reason that modem cards don't work in the Poqet.  IBM-compatible serial
ports work by transferring data to/from I/O registers.  When a PCMCIA card
has I/O registers, then it's PCMCIA Revision 2.0 compliant, and the Poqet
doesn't support PCMCIA Revision 2.0.  I don't like to say anything for
certain until I test it out myself, but I'm pretty sure that a serial port
PCMCIA card wouldn't work in the Poqet PC.

The RS-232 port on the Poqet PC -- the signals coming right out of the
expansion port on the back -- runs at either +/-6v (with Power Management
enabled) or +/-9v (with Poqer Management disabled -- which is one more
reason to do serial communications with Power Management disabled).  I just
used a voltemeter to check the voltage, and I actually measured voltages of
6.62v and 9.91v, but as your batteries drain, these voltages may drop to 6v
and 9v, respectively.  

The RS-232 standard actually calls for any voltage between 3v and 25v to be
recognized as "on" and voltages from -3v to -25v to be recognized as "off".
 All the RS-232 serial devices I've ever seen will happily accept RS-232
signals that are +/-9v, so you should have no problem interfacing with
almost any RS-232 serial device under the sun.  

It is true that there is a charge pump in the Poqet, it's just that it
pumps it up to voltages that are generally acceptable for RS-232
communication.  The Poqet PC Plus did have a second "TTL" serial port, that
ran at 0-5v, but the serial ports in the Poqet PC Classic and Prime run at
+/-9v.

Also, the pinouts for the Poqet PC expansion port are on the Web Site, in
the FAQ at <http://www.best.com/~bmason/PoqetPC/faq.shtml#Pinouts> and in
the Tech Ref Manual at
<http://www.best.com/~bmason/PoqetPC/techref/chapter6.html>.

-- Bryan

>On Wed, 2 Jul 1997, Lo Len Smucker <lolen@xxxxxxxx> wrote:
>
>>I have a modem for the Poqet but cannot find a serial port adapter that
>>would go from the Poqet to the female (25 prong)plug on the modem.
>>
>>Would you have any idea as to where I could obtain same or how one could be
>>constructed?
>>
>>Thanks in advance for any help.
>>
>>Len

And then, at 08:23 AM 7-4-97 -0700, Ron W. Hardy <compass@xxxxxxxx> wrote:
>
>Hello Len,
>
>Yes, perhaps I can help. 
>
>First, there is a company that makes a serial port that uses the PCMCIA (PC
>card) slot. This would be your easiest and fastest solution. The company that
>was developing it about three years ago was Prolinear (www.prolinear.com). I
>have seen the units advertised recently in Computer Shopper and
distributed by
>Simple Somebody who also makes PC card modems.

[ --- snip --- ]

>The modified RS-232 signals generated by the Poqet are at 5 volts. Internally
>within the Poqet, the signals are 3.3 volts. But the signals are run
through a 
>'charge pump' which boosts the signal level up to 5 volts. This is why the
>batteries drain so much faster whenever you are using the serial port. The
>charge pump eats some juice to do it's stuff.
>
>Now, you will need to get a good book on how the RS-232 interface works so
>that you get it right. The classic is "RS-232 Made Easy" by I don't remember
>who. I will need to find the book and get the authors name again. 
>
>And beware, you will either need to only connect your Poqet to other
>instruments that work on 0-5 volts rail-to-rail, or you will need to add line
>buffer/drivers to your serial port design to keep from burning out the Poqet.
>
>If you fry your machine, don't say I didn't warn you. Normal RS-232 devices
>(including your desktop computer) operate at signal levels of +15 volts and 
>-15 volts rail-to-rail. Notice that this is a total voltage swing of 30 volts
>rail-to-rail. The reason that they do this is to overcome noisy environments
>and allow the signal to travel long distances and still have enough
voltage to 
>get the job done.
>
>AGAIN, IF YOU WANT TO CONNECT TO NORMAL RS-232 DEVICES (read as "anything
that 
>plugs into the wall or uses more that four single-cell batteries in series")
>THEN YOU WILL NEED TO INCORPORATE "LINE BUFFER/DRIVERS" INTO YOUR SWERIAL
PORT 
>DESIGN. These buffer/drivers can be found at Radio Shack or any well stocked
>electronics store or catalog like Mouser or JDR and they cost less than a
>dollar each as I recall.

[ --- snip --- ]

>If you think that you would like to try the adventurous route I have
outlined,
>then let me know and I will see if I can find a pinout for the Poqet I/O port
>so you will know what traces to etch on your circuit board.
>
>Cordially Yours,
>
>Ron W. Hardy
>Compass Consulting Co.
>775 South Sunset Drive
>Cedar City, UT 84720
>voice:	801-865-7000
>cell:	801-559-8000
>fax:	801-586-5248
>email:	compass@xxxxxxxx
>web:	http://www.tcd.net/~compass/



Fabricating Serial Connector by faethor@xxxxxxxx (J. Lawrence)


From: faethor@xxxxxxxx (J. Lawrence)
Subject: Fabricating Serial Connector
Date: Tue, 8 Jul 1997 09:15:31 -0500 (CDT)
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"


    Mr. Hardys suggestions as to how to make yourself Poqet->Serial adaptor
are waaaay too extensive for what is actually needed.

    If you have the tools and ability to make an etched board, terrific!
But you don't have to worry about two-sides.  You only NEED to connect GND,
TD, and RD, which are all on top, near the plastic 'tab' that keeps you from
putting the card in upside-down.  The pin-outs for GND, TD, RD are readily
available.  If they're not in your Poqet manual, they'll be on B. Mason's
Poqet page.

    If you DON'T have the ability/aptitude to do an etched board (I didn't),
one can make a perfectly functional connector with a piece of bare-board and
solid-copper wire - what I used was telephone wire.  

    Cut a piece of bareboard just long enough to fit in the Poqet bus.
Carefully measure the plastic 'tab', and cut a slot for it.  I used an
X-acto razor saw which makes very fine cuts and had to file out the cut for
the tab until it was large enough.  Sand the edges until smooth.  Make sure
it fits snuggly and DOES NOT wiggle side-to-side.  Mark the position of the
three connectors (GND, TD, RD), two are to the left of the vertical tab, one
to the right.  This requires the post precision.  Next, take pieces of
stripped copper wire and pound the ends so that they are slightly flat.
Make sure they aren't wider than the connectors!  Epoxy the three wires in
the appropriate places you marked on the bare-board.  After the Epoxy
hardens, file the front edge so no wire extends beyond.  Also file the tops
of the wires until they are quite thin.  Slip it into the Poqet.  If it
catches, don't force it.  Try filing the wires a bit more.  When it does
smoothly slide in, check to make sure the wires are over the correct
connectors, and that they ARE NOT shorting out a connector next to them!
The HARD part is over.  Now connect either a DB-9 or RS-232 to the wires..
This is a simplistic description, but should be adequate to anyone capable
of making their own adaptor.

    DON'T attempt this if you're uncomfortable with working with tools,
especially fine precision measurements.  I made one with no problems.
Worked for months until I bought a genuine Fujitsu serial-connector used.

Jay  




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Date Created: 30 Nov 1996, Last Modified: 13 May 2009
Created by Bryan Mason - E-Mail: poqetpc<at>bmason<dot>com