[time-nuts] Mounting GPS Antenna on Steel Roof

[Brian Kirby]

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.

Brian KD4FM



Bruce Griffiths wrote:
> Hal Murray wrote:
>   
>>> Well, I plugged my Oncore UT+ into my PC and it didn't work until I
>>> put a level shifter in... no damage but no data either. So far I've
>>> been lucky in that every device I tried that needed a level shifter
>>> wasn't damaged by the lack of one. 
>>>     
>>>       
>> The normal MAX232 type level shifters include an inverter.
>>
>> So even if the voltage levels work without a level shifter, the signal will 
>> be upside down.
>>
>>
>>   
>>     
> To play safe, if one isnt sure that an inverter is required or not an 
> exclusive OR can be used so that the signal can be inverted or not as 
> required.
>
> Bruce
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>