[time-nuts] TruePosition GPS Receiver

Ben Hall kd5byb at gmail.com
Tue May 9 18:00:36 EDT 2017

On 5/6/2017 8:13 PM, ziggy9+time-nuts at pumpkinbrook.com wrote:
> A few notes on the GPSDO module:
> - the 5 pin header near U19, the LM74 temp sensor:
>      - pin 5 or the third pin in the row closest to U19 is the 12v input (measured). the other 4 are all ground.
> - the 15 pin header:
>      - pins 1,2,5,6,9,10,13,14 are all ground
>      - pins 3 and 4 are 3.3v ttl level, I’m guessing another serial port
>      - pins 7 and 8 are 3.3v ttl level, and contain the same data as J2 pin 2
>      - pins 11,12 are 1 pps, 10ms, 5v

Hi Paul and list,

When you say "pins 3 and 4 are 3.3v ttl level, and contain the same data 
as J2 pin 2" does that mean that pins 7 and 8 on on the 15 pin header 
are the RX/TX pair TTL side of the SIPEX TTL-to-RS232 chip?
One of the things I was hoping for was to find TTL access to the serial 
port so I don't have to go Arduino TTL to RS232 off-board and then go 
back from RS232 with the Sipex chip on the board.

Have taken a look-see on pins 3 and 4 to see if there is any serial data 
coming in / going out of there?

thanks much,

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