[ntp:questions] Inexpensive OEM GPS units?

Hal Murray hal-usenet at ip-64-139-1-69.sjc.megapath.net
Tue Nov 13 02:38:40 UTC 2007

>> Well, one downside is that it's "free" plus the time, materials, and
>> knowledge to make yourself a custom cable, do RS-232 level-shifting,
>> and provide a voltage source.
>Perhaps I missed something here. But all I had to do was find a serial
>header cable in my junk box, look up the Soekris header pin out,
>match the connections, solder, and plug it in. For some odd reason it
>JustWorks(tm). Didn't need an RS-232 level shifter.

The PPS signal is TTL rather than RS-232.  (It's probably actually
CMOS rather than TTL.)

Some people think you need a level shifter.  Reality says
you don't, at least on most systems including mine and yours.

I expect there are a few RS-232 ports that won't work.  I think
they may have tweaked the RS-232 specs to handle this case

These are my opinions, not necessarily my employer's.  I hate spam.

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