[aprssig] Re: GPS 18 data needed

[Stephen H. Smith]

Concerning the GPS18:

Beware!   The GPS18 does not output true bi-polar rS-232.  It behaves 
somewhat like the TinyTrak in that it outputs only "half 232"  0/5 volt 
logic levels.    If your device needs true -8VDC/+8VDC true RS-232 
levels, it may not work with the GPS18.    Apparently they decided to 
leave out a negative voltage generator in the GPS18. 

Oddly, the Garmin ForeTrex 201 Wrist GPS (where you would think space 
and power limitations would provide more of an incentive to leave out 
the negative power supply) DOES output true RS-232.....






Stephen H. Smith    wa8lmf (at) aol.com
EchoLink Node:      14400    [Think bottom of the 2M band]
Home Page:          http://wa8lmf.com

"APRS 101"  Explanation of APRS Path Selection & Digipeating
  http://webs.lanset.com/wa8lmf/DigiPaths

Updated APRS Symbol Chart
  http://webs.lanset.com/wa8lmf/miscinfo/APRS_Symbol_Chart.pdf   


New/Updated "Rev G" APRS     http://webs.lanset.com/wa8lmf/aprs
Symbols Set for UI-View,
UIpoint and APRSplus: