"David J Taylor" <david-tay...@blueyonder.neither-this-bit.nor-this.co.uk> writes:
>Unruh wrote: >[] >> OK, interesting if true. YOu are saying that if you cut the lighter >> adapter >> off, you should supply 4.5-5.5V But the unit claims to be serial port >> device which has a nominal 12V output. I would expect that the power >> supply would then >> be at least that. >Why not check the manual? > > https://buy.garmin.com/shop/store/manual.jsp?product=010-00321-51&cID=158&pID=223 > http://www.garmin.com/manuals/425_TechnicalSpecification.pdf >GPS 18 LVC: supply voltage 4.0 - 5.5V, 60mA @ 5.0V. >From that manual, only the GPS 18 PC comes with the cigarette lighter >adapter, and that version doesn't have the PPS output required for highest >accuracy. Yes, but that same manual says that the voltage for the 18PC version is 8-30V. It says nothing about the internal voltage being the 4.5 to 5.5 V. And the 18PC and the 18LVC are different units with different inputs and outputs. The PC is also the one with serial port output and the serial port standard says that the voltage is -12 to 12V on the serial pins. Now, many serial cards do accept 0-5V (TTL) which is why the 18LVC works on many serial ports without a voltage converter, but that is out of standard. Does the 18PC follow the standard? The manual does not say. Ie, there is NOTHING in the manual which would allow one to conclude that the actual voltage delivered to the unit is 5V rather than the 8-30 V that the manual does say that the unit requires. You might be right that a) it is the lighter adapter than lowers the voltage to 5V, and b) that the output does not follow the serial port standard of -12 to 12V, but I would like something other than your speculations to go by. >Cheers, >David _______________________________________________ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
