[ARC5] CW and Mic plugs

[WA5CAB--- via ARC5]

At the beginning of WW-II, all US Army tactical headsets, loudspeakers and 
sources (receivers and interphone amps) were high impedance.  The PL-55 and 
PL-54 shells were black.  Circa 1942, the Army (or the Signal Corps) decided 
to change over to low impedance.  This couldn't happen overnight and even 
through the end of the War there were still aircraft and vehicles with high 
impedance systems.  The problem is that in a high Z system, one low Z headset 
will kill all of the others.  So to differentiate mainly aircraft headsets, 
they came out with the red PL-354 which was used on the HS-33 and HS-38.  
I'm not aware of there ever being a red PL-55 equivalent.  And plugs on 
cables like the CD-307-A remained black.

Mic jacks with a red band are Navy.  Pre-war Navy microphones weren't wired 
the same as Signal Corps ones.  Microphone transmitter  went to Tip and PTT 
to Ring.  Around the beginning of the War or a little before, the Navy 
began a crash modification program to change all of them.  Modified (rewired) 
mic cable plugs were supposed to get a red band around the sleeve and modified 
radios were supposed to get a red washer under the mic jack retaining nut.  
Then someone must have decided that everything had been modified as the red 
band practice stopped.

In a message dated 05/29/2014 18:21:14 PM Central Daylight Time, 
jcoward5452 at aol.com writes: 
> Robert, 
>  Why the red and black shells? Does this indicate high or low impedance? 
> Some mic jacks have red paint around them, also curious about that.
>   Thanks, 
>               Jay
> 

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480