RM,

I use a Radio Shack 1/4 inch male mono phone plug to two 1/4 inch female
phone jacks splitter (RS #910-0791) and plug that into the headset jack. I
plug my 1/4 inch headset earphone plug into one jack of the splitter. I plug
a three foot long 1/4 inch male phone jack to male RCA plug cord (RS
#970-0916) into the other jack of the splitter. I plug a female RCA to male
3.5 mm 40 dB attenuator (RS # 910-0889) into the cord and plug that into my
recorder. If your recorder needs 2.5 mm you get to add yet another adapter.
It's not elegant, but it works. I plan to neaten it up some day by adding a
3.5 mm jack to the panel and wiring it through a simple attenuator directly
to the headset jack.

Caution: Radio Shack has an attenuator cable that has a 1/4 inch phone plug
on one end and a 3.5 mm plug on the other. It looks like the perfect
solution, bit it won't work well (if at all) because it's designed for an 8
ohm system and Cessnas expect to drive a minimum load of 38 ohms, according
to Jim Weir -- and he knows all about this stuff.

Jon

"Nobody" wrote in message
...
I would like to record, from the intercom system of a typical GA plane
(Cessna), to an off the shelf digital audio recorder. The question is,
how
do I go from the intercom system to the 'Mic' jack of the recorder....
without damaging either? I presume I need more than just a 2.5mm adapter
for the intercom system???

Thanks in advance

-RM