[ntp:questions] almost decided which new PPS GPS to buy

Ron Frazier (NTP) timekeepingntplist at c3energy.com
Mon Mar 5 19:48:44 UTC 2012

On 3/5/2012 11:52 AM, David Lord wrote:
> Ron Frazier (NTP) wrote:
>> On 3/5/2012 9:45 AM, Chris Adams wrote:
>>> Once upon a time, Ron Frazier 
>>> (NTP)<timekeepingntplist at c3energy.com>  said:
>>>> 2) Motherboard header - DB-9 port adapter
>>> Note that there are two different pinouts common for this.  IIRC they
>>> all have the same mapping of motherboard header pin number to serial
>>> port pin number, but one numbers the header pins in rows and the other
>>> in columns.
>> Thanks for bringing that to my attention!  AARG!  Not yet ANOTHER non 
>> standard connector.  I didn't know that.  Here's what the manual says 
>> my motherboard com port connector looks like.  Each pin is an X:
>> 9 X   X   X   X   X 1
>>       X   X   X   X 2
>> 1 = DCD
>> 2 = Rx
>> etc.
>> Can anyone tell me the right adapter to bring it out to the rear 
>> panel.  I usually like to purchase on Amazon.
> It depends on your motherboard so you need to order the
> cable plug and D9 plug for that particular board. I usually
> find I have the correct combination but if not it's usually
> cheaper and quicker to make a suitable cable assembly.
> David


Thanks for the data.  I've been doing some research on RS-232 
connectors.  Ever since the year 2000 or so, I NEVER thought I'd be 
fiddling with this technology again.  Oh well, whatever works I guess.

Here are some links for the pinout of the DB-9 serial connector.


The third one is the most detailed, and gives the pinouts for the PC 
male connector (known as DTE or Data Terminal Equipment [if I recall 
correctly]), and the modem female connector (known as DCE or Data 
Communications Equipment [if I recall correctly]).  In this case, I'm 
interested in the PC side or DTE.  That's what the first two links refer to.

Googling around for the motherboard connector provided these:

http://www.pccables.com/07120.htm - Straight through wiring - 12"
http://www.pccables.com/07130.htm - Straight through wiring - 30"
http://www.pccables.com/07121.htm - Cross over wiring - 12"

Based on consulting my motherboard manual, I've determined that I need 
the straight through wiring, so I'm buying the 30" model.




(PS - If you email me and don't get a quick response, don't be concerned.
I get about 300 emails per day from alternate energy mailing lists and
such.  I don't always see new messages very quickly.  If you need a
reply and have not heard from me in 1 - 2 weeks, send your message again.)

Ron Frazier
timekeepingdude AT c3energy.com

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