Homemade Model T Null Modem adapter

November 11, 2010 on 6:28 am | In Hacks | No Comments

It is me again, on of my biggest issues in data transfer is the issue it null modem adapter, the large variety and difficulty finding the right one so I decided to make one.  I used the diagram from the Club 100 website to make mine.  http://www.club100.org/library/doc/cables.html and it works well.  So here is what you need.

Materials: (all from radio shack)

Male 25 Pin D-sub connector crimp style (276-1429)

(connects to your Model T)

Female 9 Pin D-sub connector crimp style (276-1428)

(connects to you 9 pin serial port or to an usb serial port adapter)

D-Sum pin Inserter/ Extractor (276-1426)

(make fixing mistakes much easier when you put the wrong pin in the wrong place or a if a wire pulls out)

I also purchased a 25 pin D-sub hood and a 9 pin D-sub hood to hold it.  next time I might just use some epoxy or shrink wrap.

Wire, I use 22 gauge wire of 3 colors to make life easier.

How it works:

A null modem cable crosses over some pins between computers and with in the computer’s serial port.  Different computers, devices, and programs requite different wires and pins to be crossed and jumped.   So make sure you have the right diagram http://www.club100.org/library/doc/cables.html.

To get started read the diagram one more time  Then cut your wires to the right length and crimp on the pin connectors.   If you look closely you can see the numbers cast into the connector plastic.  Push the pin in until it clicks.

Notice how some wires go to the other connector and how some loop back to the computer.

The Female adapter has a different looking pin to accept the male fitting from the usb adapter.  Crimp those on and gently push them in to the right place.  When you are done both connectors will be connected by 3 wires.

Time to test.   Go in to hyper terminal on your desktop and go to telecom on your Model T and test the adapter.  This is a great tutorial on how to just that.  http://bitchin100.com/wiki/index.php?title=Text_File_Transfer_using_Hyperterminal

This is the very netbook, that I became tired of in class, too much device or fighting for a power outlet just to take notes.  If you can look on the screen you will see test that I transferred from the 102 thru Hypertemial.  The process does work in reverse.

Now finish and protect your cable.  That is what I am using the D-sub Hoods are for.   Put them on and use the included hardware to secure.

Tada.. you are done.   Now use this to assist you in your file and text transfer needs.   Remember to be patient.  The transfer might be going at 19.2kps but the Tandy had a processor running at 2.4mhz (your computer is probably in the 2.4 ghz range which is 1000x faster) downloading to it may take a few minutes for the file or text to be processed.

check back soon for my next project and blog

No Comments yet »

RSS feed for comments on this post. TrackBack URI

Leave a comment

XHTML: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>

Powered by WordPress with Pool theme design by Borja Fernandez.
Entries and comments feeds. Valid XHTML and CSS. ^Top^