[ARC5] "Retaining" plugs

[Christopher Bowne]

Should have read this post before I doubled up on it with mine!




________________________________
 From: Mike Everette <radiocompass at yahoo.com>
To: jfor at quikus.com 
Cc: arc5 at mailman.qth.net 
Sent: Thursday, July 4, 2013 11:48 AM
Subject: Re: [ARC5] "Retaining" plugs
 

That's the reason for the "short" 1/4 inch plug on headsets, and the CD-307 headset extension cord with a jack on the end to accept the short plug.

This was known as a "Bail-Out Plug."  The plug and jack would separate in the event of a need to bail out.  This was especially easy to disconnect in a fighter, if the pilot had only to roll the a/c inverted, unfasten the seat belt and fall out.

Remember, many headsets -- probably most -- were actually part of the leather flight helmet, and therefore couldn't be just taken off and left in the a/c.

73

Mike
W4DSE

--- On Thu, 7/4/13, J. Forster <jfor at quikus.com> wrote:

> From: J. Forster <jfor at quikus.com>
> Subject: Re: [ARC5] "Retaining" plugs
> To: "Mike Everette" <radiocompass at yahoo.com>
> Cc: arc5 at mailman.qth.net
> Date: Thursday, July 4, 2013, 9:34 AM
> Somehow, if I were in a plane along
> with a lot of avgas, ammo, and bombs,
> being shot at, I'd really not want screw fastenings on my
> headset cord
> that needed to be unscrewed in order to make a fast exit.
> 
> YMMV,
> 
> -John
> 
> ==================
> 
> 
> 
> 
> > I've seen a number of the PL-68/PJ-068 connectors with
> threads protruding
> > beyond the plastic shell, on a couple of different
> types of microphones.
> > Off the top of my head I don't remember any
> PL-55/PJ-055 crossing my path
> > that have the threads exposed but there may well have
> been.  At a hamfest
> > a couple of years ago I bought a bunch of "new" headset
> extension cords
> > like the CD-307, I'll look them over more closely.
> >
> > Truth be told, I never thought of the exposed threads
> being for a
> > retaining device; I just thought that for some reason
> the shells didn't
> > screw all the way on (duuuuh).  I've either
> repaired or installed numerous
> > of these plugs in ham apps and gen-av avionics, so yes,
> I've seen a few.
> >
> > As an aside, Motorola uses a similar idea with their
> "audio adapter"
> > devices employed with current hand held radios, when
> headsets or earpieces
> > are in use.  The plugs are 1/8 inch instead of
> 1/4; but they do have some
> > exposed threads to lock the cord into the adapter,
> which is attached to
> > the side of the radio (that's what the exposed flush
> gold plated terminals
> > on the side are for, in addition to programming-cable
> connection).
> >
> > Back to the matter of WW2 gear, I would think that
> oxidation or corrosion
> > of the brass PL-55/68 etc especially in humid climates
> would have been a
> > far more serious problem than plugs popping out,
> though.  I've cleaned
> > quite a few myself when audio, either receive or
> transmit, got scratchy or
> > intermittent.
> >
> > 73
> >
> > Mike
> > W4DSE
> >
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> 
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