David Clark Isocom - how does it work?

[John Clonts]

We have this intercom unit in our 210 and it has worked fine in the
four years we have owned the plane.

<http://www.davidclark.com/IntercomSys/isocom.htm>

However, there is the toggle switch on the unit labeled "Isocom". We
have always left this switch in the "Off" position, because if we turn
it to the "Isocom" position no one can hear anything at all (neither
the pilot nor copilot nor any passengers nor the radios).

We suspect that the "Isocom" position is intended to isolate the
pilot/copilot from the passengers, but the manual (accessable from the
above webpage) has NOTHING on what exactly it is supposed to do.

Could someone with experience with this particular unit please answer
these questions about the "Isocom" mode, and add any other relevant
details?

With Isocom "on":
The pilot and copilot can hear each other, and ATC communication?
The pilot/copilot can hear the passengers?
The passengers can hear the pilot/copilot?
The passengers can hear the radios?
The passengers can hear each other?

--
Thanks!
John Clonts
Temple, Texas
N7NZ

[Mike Adams]

"John Clonts" > wrote:

> We have this intercom unit in our 210 and it has worked fine in the
> four years we have owned the plane.
>
> <http://www.davidclark.com/IntercomSys/isocom.htm>
>
> However, there is the toggle switch on the unit labeled "Isocom". We
> have always left this switch in the "Off" position, because if we turn
> it to the "Isocom" position no one can hear anything at all (neither
> the pilot nor copilot nor any passengers nor the radios).
>
> We suspect that the "Isocom" position is intended to isolate the
> pilot/copilot from the passengers, but the manual (accessable from the
> above webpage) has NOTHING on what exactly it is supposed to do.
>
> Could someone with experience with this particular unit please answer
> these questions about the "Isocom" mode, and add any other relevant
> details?
>
> With Isocom "on":
> The pilot and copilot can hear each other, and ATC communication?
> The pilot/copilot can hear the passengers?
> The passengers can hear the pilot/copilot?
> The passengers can hear the radios?
> The passengers can hear each other?
>

I haven't used this unit, but from looking at the manual, it appears the switch turns the whole unit off,
and routes the audio input from the radios or audio panel directly to the output. The installation notes
say that you can adjust the audio level to be the same, with the switch either on or off. Is it possible the
audio level is all the way down, and you're not getting any output in the ON position? I don't believe
there's any pilot or copilot isolation because the block diagram shows just a single output going to all
the headphone jacks (so pilot, copilot, and passengers will always be getting the same output).

Do you get normal intercom function in the OFF position, i.e. can you hear your passengers talk? You
will get normal sidetone from the radios, so just hearing yourself or your copilot talking while
transmitting on the radio could work even without the intercom working.

Maybe someone else has actually used this unit, and can help further.

Mike

[John Clonts]

Thanks for looking into it-- comments below


"Mike Adams" > wrote in message news:71izf.9595$jR.6179@fed1read01...
> "John Clonts" > wrote:
>
>> We have this intercom unit in our 210 and it has worked fine in the
>> four years we have owned the plane.
>>
>> <http://www.davidclark.com/IntercomSys/isocom.htm>
>>
>> However, there is the toggle switch on the unit labeled "Isocom". We
>> have always left this switch in the "Off" position, because if we turn
>> it to the "Isocom" position no one can hear anything at all (neither
>> the pilot nor copilot nor any passengers nor the radios).
>>
>> We suspect that the "Isocom" position is intended to isolate the
>> pilot/copilot from the passengers, but the manual (accessable from the
>> above webpage) has NOTHING on what exactly it is supposed to do.
>>
>> Could someone with experience with this particular unit please answer
>> these questions about the "Isocom" mode, and add any other relevant
>> details?
>>
>> With Isocom "on":
>> The pilot and copilot can hear each other, and ATC communication?
>> The pilot/copilot can hear the passengers?
>> The passengers can hear the pilot/copilot?
>> The passengers can hear the radios?
>> The passengers can hear each other?
>>
>
> I haven't used this unit, but from looking at the manual, it appears the switch turns the whole unit off,
> and routes the audio input from the radios or audio panel directly to the output.

I don't think so because the audio volume and squelch work with the switch in the off position. I can hear all
my passengers.

>The installation notes
> say that you can adjust the audio level to be the same, with the switch either on or off. Is it possible the
> audio level is all the way down, and you're not getting any output in the ON position?

Yes good point, I will experiment with this...

> I don't believe
> there's any pilot or copilot isolation because the block diagram shows just a single output going to all
> the headphone jacks (so pilot, copilot, and passengers will always be getting the same output).
>

I noticed that too. Perhaps though the intent of the "Isocom" mode is that all the passengers microphones are
shut off? This is what I had hoped for that day I took four rowdy kids on a trip-- we ended up having to
unplug their mics :)

> Do you get normal intercom function in the OFF position, i.e. can you hear your passengers talk?

Yes

> You
> will get normal sidetone from the radios, so just hearing yourself or your copilot talking while
> transmitting on the radio could work even without the intercom working.
>
> Maybe someone else has actually used this unit, and can help further.

That's what I figured since the manual doesn't describe what it's supposed to do...

Thanks again,
John

[Denny]

Had an Isocom in my Super Viking... was never impressed with it
although it functioned..
The on-off switch is just that... When the intercom is turned off, the
radios will still feed through to your headset... The idea is to adjust
the Isocom so the audio level is the same, on or off... There are two
audio adjustment pots...
Look at the manual, here:
http://www.davidclark.com/PDFfiles/ISOCOM.pdf

denny

[Blanche]

I've got the PSEng audio panel and the ISO switch eliminates all
in-aircraft communication -- in other words, everyone can talk
among themselves but I don't have to listen to it. Of course,
ATC and such is still active with no problems.

It's lovely when you have no interest in what the peanut gallery
is blathering about.

[John Clonts]

Never mind, I figured it out. User error :)

Mike and Denny, you were exactly right. With the intercom off no one
can hear each other, but can hear the radios...

Thanks
John

[Jay Honeck]

> It's lovely when you have no interest in what the peanut gallery
> is blathering about.

Amen to that! With two kids in the back, that little switch is a Godsend.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Mike Spera]

Jay Honeck wrote:
>>It's lovely when you have no interest in what the peanut gallery
>>is blathering about.
>
>
> Amen to that! With two kids in the back, that little switch is a Godsend.

The old PS Engineering intercom in my bird is similar. It has "All",
"Crew", and "Pilot" switch positions. When the wife is flying shotgun in
the right seat and her friend(s) is(are) in the back, I can isolate
myself. When we have a parent/child or 2 kids in the back and the wife
and I need to pay attention on an IFR arrival, we can isolate the back
folks from us.

Whoever though of this little feature was definitely having a good day.
Mike

[Newps]

> Jay Honeck wrote:
>
>>> It's lovely when you have no interest in what the peanut gallery
>>> is blathering about.
>>
>>
>>
>> Amen to that! With two kids in the back, that little switch is a
>> Godsend.

When the kids go with us they get their own intercom. I have a portable
that I have had since my renting days. If they want to talk to the
front seats they can plug into the regular intercom jacks.