Chris is correct many GPS receivers do not output anything till queried. Further it seems the TX and RX data may need to be swapped. That has bagged me a few times because it depends on the perspective. Easier to just try swapping them. The max series does indeed perform the the logic translation a +5 signal ttl/cmos to -12V rs232. Regards Paul WB8TSL
On Wed, Jun 11, 2014 at 1:50 PM, Chris Albertson <[email protected]> wrote: > First off if you are getting PPS on the PPS pin the GPS is working. By > default I don't think the MT12 outputs any serial data unless in response > to a query. By default it is not a NEMA device. > > The protocol is binary so it would be rely hard to control it with a Window > terminal program > > The simplest way to use the MT12 is to connect it to an NTP server. You > may not want to run NTP, you want a GPSDO but NTP knows how to get the MT12 > running and NTP has a good log file that you can read to track what the GPS > is doing. There are other software for controlling MT12 and other Oncore > series GPSes that are better but NTP is already installed on many computers > > The other thing to watch with serial RS232 is the polarity. I'm pretty > sure the MAX chip acts as an inverter. That might be good because RS232 > uses negative logic with a low voltage being a "one" and a higher voltage > being a "zero" Well at least on the data pins, the control, I think is > positive logic. If you get the polarity wrong it does not work > > > > On Wed, Jun 11, 2014 at 9:04 AM, Stephen <[email protected]> wrote: > > > Hello everyone, > > > > After reading quite a bit from your archives i've decided to try a put > > together a 10MHz reference. > > > > I've picked up a oncore M12+T GPS card and have tried to initialise it > but > > without any success thus far. > > > > The user manual for the M12+T seems to suggest that i should be able to > > hook the txd and rxd pins to a MAX3232 and be able to use the Winoncore > > software to configure the card. > > > > At power up the M12+T pins 1 & 2 are at 3V. After 10 seconds pin 2 sinks > > to 0V, pin 1 idles at 3V and pin 4 give 1PPS. No serial output from the > > card at all. > > > > Anyone have experience of connecting an M12+T to rs232? > > > > Stephen > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > > -- > > Chris Albertson > Redondo Beach, California > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
