[time-nuts] Mounting GPS Antenna on Steel Roof

GandalfG8 at aol.com GandalfG8 at aol.com
Sat Mar 8 03:48:23 EST 2008


 
In a message dated 08/03/2008 03:57:02 GMT Standard Time,  
kirbybq at bellsouth.net writes:

The  inverter is required because the Motorola GPS receiver uses TTL and 
the PC  serial port uses RS232.

RS232 uses a positive voltage of +3 to +25  volts to indicate a logic 
zero, and a negative voltage of -3 to -25 volts  to indicate a logic one.



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My Motorola Oncore test rig uses a Max232 to interface the RS232, no  
inverter, and works fine.
 
regards
 
Nigel
GM8PZR



   


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