From: ap@dde.dk (Allan Petersen)
Newsgroups: comp.sys.palmtops
Subject: $US 3.00 Serial cable kit for HP48/HP95
Date: 23 Nov 92 14:33:02 GMT
Organization: Dansk Data Elektronik A/S


I posted this on c.s.hp48 some days ago. It may be of
interest to others as well, so I now post it on 
c.s.handhelds and c.s.palmtops:
-----------------------------------------------------------


Now the FINAL  "Cheap do-it-yourself serial cable kit:"
                --------------------------------------

I've now found a commercial 4 pin connector with a 2 mm pin
spacing suitable for  the serial port on a HP48S, HP48SX or
HP95LX.

It's an AMP connector type 173977-4.  However, it uses  IDC
(Insulation Displacement Connection)  termination  and will
thus require a special hand tool to attach a cable.

I was able to borrow this hand tool, so I bought a  bag  of
connectors to make some cables.  I will now offer these for
sale to people on the net.

Shipping all the cables individually to the States  (were I
assume the main number  of buyers are anyway) doesn't sound
very  efficient to me, so now  Joel Kolstad  has agreed  to
distribute the cables "locally", and I've  shipped a box of
cables to him. The cables should then be available soon.

The serial cable kit consists of a connector attached to  a
short (6 to 7 inches) length of (flat) cable. The other end
of the cable is unterminated to  enable  you  to  attach  a
suitable  DB25/DB9/other  connector or extend the cable  at
your own choise.  The cable comes with instructions on  how
to wire the DB25/DB9 connector.

The price will be US$ 3.00 for each cable.

Ordering instructions:    Send your order, a Self Addressed
                          Stamped  Envelope, and  $US  3.00
                          (for each cable) to:

                          Joel Kolstad   
                          Room 1310 ERB
                          1500 W. Johnson Dr.
                          Madison, WI 53706
                          USA

Joel will then mail the  cable(s)  and  the instructions to
you (he promised :-)).  He also  promised to post a message
on the net in case he runs out of cables.....

Anyway, if you  have any  questions,  you can reach Joel by
email:   kolstad@cae.wisc.edu

Allan Petersen,   ap@dde.dk

---------------------------------------------------------------
This is the describtion that comes with the $3 Serial cable kit:
---------------------------------------------------------------

CABLE KIT for HP48S, HP48SX and HP95LX:

Using  the cable  is  described in  the manual for  HP48SX  in 
chapter 33, "Transferring Data to and from the HP48."

The pin connections are described in several places,  e.g.  in
The  HP48  Handbook by James Donnelly,  in several articles on
c.s.hp48 and in the FAQ file sometimes posted on c.s.hp48.


>From the recent FAQ:

30. What are the pinouts for the HP 48SX serial connector?

Looking  at  the pins of the HP 48SX (the following diagram is
showing the pins  on  the  HP  48SX,  as  you  look  *AT*  the
calculator):
                 _________
                | o o o o |
                 \_______/
                  ^ ^ ^ ^
                  | | | \------ 4 Signal GND
                  | | \-------- 3 RX (input to the HP 48SX)
                  | \---------- 2 TX (output from the HP 48SX)
                  \------------ 1 SHIELD

Stated another way:

HP48SX                             IBM 9 PIN          IBM 25
(From the outside
edge -> inward)
SHIELD--------Yellow-or-Grey-------SHIELD (1)-------- SHIELD (1)
TX (Output)---Orange-or-Violet---->2 RX (Input)------>3 RX (Input)
RX (Input)<---Red----or-Blue-------3 TX (Output)------2 TX (Output)
SGND----------Brown--or-Green------5 GND--------------7 GND
                                   4 DTR---!          5 CTS--!
              ^                    6 DSR---!          6 DSR--!
              Colour code          8 CTS---!         20 DTR--!
              on cable kit

The  cables  comes  with  one  of the indicated colour codings
(brown,red, orange,yellow or green,blue,violet,grey).

On the 9 pin connector you may have to wire pin 4,  6,  and  8
together  and  on  the  25  pin connector you may have to wire
together pin  5,  6,  and  20.  This  is  required  with  some
computers (to have CTS and DSR active),  but it may not always
be required.

The other day I had the chance to try a new cable on  a  brand
new 48SX.  It worked fine, but I had to press the connector in
place with the tip of  a  screwdriver  until  a  slight  click
announced  that  it was correctly seated.  I never experienced
that  with my  own  old 48SX.  I better  mention it  here,  or
somebody might think the cable isn't working reliably :-).  It
really *is* important to press  the  cable  firmly  in  place,
until  the  cable has been used some times.  I have now used a
cable like this for more than half a year,  and it has  always
worked fine.

Enjoy  your new cable and all the useful software to which you
can   now   have   access.   Long   live   comp.sys.hp48   and
comp.sources.hp48...
                    ...and hp-mail-server@seq.uncwil.edu   :-)

Allan Petersen
ap@dde.dk
Newsgroups: comp.sys.palmtops