That's sort of like asking the difference between "high power" and "low power"
for engines. The answers will be totally different between the warbird driver
and the ultralight pilot.

However, in general, "high impedance" in an avionics device means some value in
excess of 1k ohm...more like 10k ohms. Low impedance is less than 1k.

HOWEVER, some manufacturers mean "high impedance" to be phones level (150 ohms)
and "low impedance" to be speaker audio (4-8 ohms or so).

The problem is that you need to do some more digging about the DME in question.

Now *I'VE* got a stupid question of you. DME is a dinosaur. Why in heaven's
name are you loading your airframe with that amount of ironmongery just to give
you about 1% of what a good GPS at 1% of the weight will give you?

Jim


(JFLEISC)
shared these priceless pearls of wisdom:

-I could use some wiring help here. I'm not that good at the terminology but I
-know that and always ask advice, so things usually turn out right.
-Question; I'm wiring in a used DME and the ident (audio) output has a choice
of
-'high impedance out' or 'low impedance out'. What's the difference? Is one for
-direct to headset and the other for going through the amp in the nav/comm
-receiver or something like that? Thanks in advance.
-
-Jim


Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com