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[wxsig] Connecting T238+, X1W-1. X1W-2 and AAG, Second Attempt

John Koster w9ddd at tapr.org
Sun Jul 8 17:04:21 UTC 2007


Well, I still had problems, so I made this attempt to restore to original 
format.

Situation 1
                Pin Number
                Device
*6 Pin RJ 11*   *4 Pin RJ 11*   *T-238+*   *X1W-1*   *X1W-2*  *AAG*
 1               
 2               1               gnd        +5V       +5V      Vcc
 3               2               Bus        Bus       Bus      Bus
 4               3               gnd        gnd       gnd      gnd
 5               4               +5V                           gnd
 6

X1W-1 P17 jumper connect pins P and 2
X1W-2 JMP3 jumper connect pins P and 2

Situation 2

                Pin Number
                Device
*6 Pin RJ 11*   *4 Pin RJ 11*   *T-238+*   *X1W-1*   *X1W-2*  *AAG*
 1                
 2               1               gnd                            Vcc
 3               2               Bus        Bus       Bus       Bus
 4               3               gnd        gnd       gnd       gnd
 5               4               +5V        +5V       +5V       gnd
 6

X1W-1 P17 jumper connect pins  P and 1
X1W-2 P JMP3 jumper connect pins P and 1


A little history, as I remember it,   Seems like the 3rd rev of the AAG WX 
STN came out while the T238+ was in the final stages of going into kit 
production, so there wasn't much chance of modifying it.  John was still 
working with alpha versions of his two boards, so he hedged his bet and 
put the jumper options.  No one has ever come up with an explantion as to 
why AAG decided to be different.  

What can be done?  Seems I remember some doing a trace cut on either the 
T238 or the AAG.  I'm not excited about that option.  

How many of the devices listed need power from the cable?  I guess that 
might depend on your configuration.  My original Dallas WX STN did not 
require anything but the 1-wire bus and ground.  Same with the rain gauge.

Are there any other 1-wire devices that might enter into the picture?  
What is there +5 situation?

If all we need to consider are the devices Leon has listed, then here's my 
take.  Either a trace cut on the T238+, or a 'twist' in the cable leaving 
the T238+, where the 'wrong' connector is on the T238 end.  Everything 
thing else downstream is then just a loop through and is configured to be 
compatible with the AAG.  

Another question.  As far as everyone knows, has the pin numbering been 
consistant throughout all this discussion.  I mean, do TAPR, AAG and any 
others all number the pins the same?  I should know this since I did the 
PCB layout for the original T238, but I was concerned with the pin 
numbering at the PCB interface and really took no note of how it looked 
from the mating connector side.

I'd like to be able to post the concensus and/or recommendation on TAPR
web pages, so the question doesn't keep comming up.

 -- 
73,
John, W9DDD





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