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[aprssig] Confusing situation

Ray Wells vk2tv at exemail.com.au
Wed May 14 21:24:29 UTC 2008

Mmm, reminds me of the hours I spent trying to get a Baycom modem to 
work, only to eventually find the db25/9 adaptor was only wired for data 
and not all pins!

Ray vk2tv

Andrew Rich wrote:

> Ever have one of those days ?
> 1. I have a little plug pack with a variable slider 12V, 9V etc
> 2. The plug pack powers a PIC development board (PIC and MAX232)
> 3. The development board has a MAX232 on board which I am using to 
> send to the laptop.
> 4. Data was coming in on the radio chip, and 5 volts logic was being 
> presented to the MAX232. (used a CRO)
> 5. Tried a different USB / Serial converter - same, no data in hypertrm
> 6. Reboot windows.
> 7. It turned out that the little plug pack had slid from 12 volts to 9 
> volts.
> 8. It was enough for the little LED cct to show it was working, but 
> not enough to get the MAX232 to work.
> Annoying.
> Loop back on serial worked - just to confuse me even more.
> Looked on PIN 2 with a CRO and saw data - but the CRO ust a high Z and 
> did not load up the cct.
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