---- The Poqet PC --------------------------------------------------------------
 Home  FAQ  LIST  SOFTWARE  DOCUMENTATION  MUSEUM  LINKS

Poqet PC Mailing List Digest
Volume 001, Number 137, 18 Jul 1997

Table of Contents


 <
Previous (Vol. 001, No. 136)

UP (to archive list)
 >
Next (Vol. 001, No. 138)

  1. Home-brew serial port and a hello! by Jerry Glenwright <j.glenwright@xxxxxxxx>
  2. Expanding D: RAM drive by Jerry Glenwright <j.glenwright@xxxxxxxx>
  3. Re: Expanding D: RAM drive by Bryan Mason <bmason@xxxxxxxx>
  4. Re: Home-brew serial port and a hello! by Bryan Mason <bmason@xxxxxxxx>

Digest Articles

Home-brew serial port and a hello! by Jerry Glenwright <j.glenwright@xxxxxxxx>


From: "Jerry Glenwright" <j.glenwright@xxxxxxxx>
Subject: Home-brew serial port and a hello!
Date: Thu, 17 Jul 1997 22:43:10 +0100
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit

First, hi, I'm a new subscriber and this seems to be an excellent source of
material, support (and shoulders to cry on!) for Poqet users.

I live in England and have been completely unable to find either a serial
cable or suitable PCMCIA cards. After owning a Poqet (640K model) for two
years or so, and finding myself desperate to get some software into that
machine (I'm into ham radio and wanted to get some weather fax receive
software into the Poqet to use it as a portable station with a pocket Sony
shortwave radio) I decided to build my own serial interface.

I've built projects and upgraded various computers (principally, Atari
8-bit machines) many times over the years but I wouldn't say I was an
electronics expert. I thought that etching a board might be a possibility
but first, I thought I would look in my junk box. I found there a broken
2Mb 72-pin SIMM which had the exact same .5mm edge connector spacing
required. 

I cut the SIMM in half and removed the chips. Then I identified which
connectors I needed and removed the others. I stripped some fine wires and
soldered them to the connectors on the SIMM and a 25-pin D-plug. I filed
the now-too-thick board on its underside so that it would slip easily into
the port on the Poqet. I then held my breath, and pushed the connector
home. It worked just fine.

I tried it with a null-modem attached to my Mac and swapped data to and
fro. Then I connected it to my PC with the same perfect results. I felt
very pleased with myself... I decided that now I'd proved to myself that it
could be done, I would etch a 'proper' board and build myself a nice
interface. However today, after discovering the mailing list archives, I
read the message from Ron W. Hardy and felt my legs wobble beneath me! I
might've killed my poor old Poqet PC!

OK, so can anyone help with the chip numbers of a suitable line
driver/buffer as mentioned in Ron's posting? Also, my interface is working
just fine at the moment but is it about to fry my machine? 

Also, does anyone know of a supplier able to sell me a serial cable and
PCMCIA cards and ship them to England for a reasonable price? I tried
California Digital's email address but my mail is bounced back to me.

Sorry for this long and boring posting. I'll try not to be so verbose in
future...

Best wishes

Jerry Glenwright


Expanding D: RAM drive by Jerry Glenwright <j.glenwright@xxxxxxxx>


From: "Jerry Glenwright" <j.glenwright@xxxxxxxx>
Subject: Expanding D: RAM drive
Date: Thu, 17 Jul 1997 22:48:14 +0100
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit

Hi,
Sorry, I meant to include this with my first posting and forgot!

Is it possible to assign more system RAM to the D: drive? I didn't get a
manual with my Poqet (640K model) so my solution is to set up another RAM
drive using a customised CONFIG.SYS and the MSDOS RAMDRIVE.SYS driver.This
seems a bit pointless, especially as the software defaults to drive D: and
has to be redirected to point to the virtual drive E:

Many thanks in advance of your help

Jerry


Re: Expanding D: RAM drive by Bryan Mason <bmason@xxxxxxxx>


From: Bryan Mason <bmason@xxxxxxxx>
Subject: Re: Expanding D: RAM drive
Date: Thu, 17 Jul 1997 17:22:26 -0700
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"


Sorry, the size of drive D: is fixed.

-- Bryan

At 10:48 PM 7/17/97 +0100, Jerry Glenwright wrote:
>Hi,
>Sorry, I meant to include this with my first posting and forgot!
>
>Is it possible to assign more system RAM to the D: drive? I didn't get a
>manual with my Poqet (640K model) so my solution is to set up another RAM
>drive using a customised CONFIG.SYS and the MSDOS RAMDRIVE.SYS driver.This
>seems a bit pointless, especially as the software defaults to drive D: and
>has to be redirected to point to the virtual drive E:
>
>Many thanks in advance of your help
>
>Jerry


Re: Home-brew serial port and a hello! by Bryan Mason <bmason@xxxxxxxx>


From: Bryan Mason <bmason@xxxxxxxx>
Subject: Re: Home-brew serial port and a hello!
Date: Thu, 17 Jul 1997 17:22:27 -0700
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"

Hi Jerry,

Great story about the SIMMs.  I used to have a bunch of old 256K SIMMs,
that I could've converted to good use.  Oh well.

You shouldn't need line buffers or drivers.  The Poqet PC Classic and Poqet
PC Prime (but not the Poqet PC Plus) provide the correct voltages.  The
standard serial adapters from Poqet do not have any buffers in them or
anything like that.

-- Bryan 

At 10:43 PM 7/17/97 +0100, Jerry Glenwright wrote:

[--snip--]

>I cut the SIMM in half and removed the chips. Then I identified which
>connectors I needed and removed the others. I stripped some fine wires and
>soldered them to the connectors on the SIMM and a 25-pin D-plug. I filed
>the now-too-thick board on its underside so that it would slip easily into
>the port on the Poqet. I then held my breath, and pushed the connector
>home. It worked just fine.

[--snip--]

>OK, so can anyone help with the chip numbers of a suitable line
>driver/buffer as mentioned in Ron's posting? Also, my interface is working
>just fine at the moment but is it about to fry my machine? 




Filename: PoqetPC/mailing-list/cgi/show-digest.htmt
Date Created: 30 Nov 1996, Last Modified: 13 May 2009
Created by Bryan Mason - E-Mail: poqetpc<at>bmason<dot>com