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Topcon GTS-235W to TSC3 Serial Connection

I am having a heck of a time getting this gun to zero from my TSC3.  The gun seems to connect as soon as I run "Station Setup" from the collector, but when I tell it to backsight it beeps but does not zero and the collector says instrument error.

The baud rate is set to 1200, parity is even, stop bits 2.  I tried going up to 4800 on the baud, but I'm really grabbing at straws.  If anyone has any know how it is greatly appreciated.


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  • Who's cable are you using?  Some of the old serial cables had a "swapped pair"  Also, Trimbles website has a pretty good knowledge base to drop this question into.

     And, why the cable? or doesn't the GTS-235W have Bluetooth?  

    This might help...

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    • Hi Kevin...

      Thanks for replying! I am using the serial cable that does work between our TSC3 and our Topcon GPT-3000.  I tried the bluetooth on the GTS-235W with multiple TSC3's.  I can create a partnership, but I am unable to establish any communication between the equipment. Per Trimbles release notes on Access Version 2015.21 third party bluetooth connections should be supported, and I did confirm that one of our DC's exceeds that I'm lost again.  Again, thank you any and all for help.



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