[GreenKeys] jackfields

[Bill Henry]

Guys,

Think safety.  The first HAL ST-6 demods used 
2-wire (TS) phone jack sockets, insulated with 
fiber washers.  But I got kicked one night when 
plugging in a machine and then we changed all 
loop connectors on the ST-6 and ST-5 to 3-wire 
(TRS) jack sockets - loop between T & R, sleeve 
grounded to the chassis..  Everyone who bought an 
early ST-6 received a retrofit kit.  We later 
switched to using Molex connectors on the 
ST-6000, ST-5000, DS-2000, DS-2050, DS-3000KSR, 
and DS-3100ASR.  The best professional 1/4" jack 
panels recess the jack socket 1/8" or more back 
into an insulated mounting panel 
(bakelite?).  The jack sockets mount to the rear 
of the panel rather than through the 
panel.  Likewise, a "professional" plug does not 
expose the sleeve barrel as you plug it 
in.  Standard 1/4 phone plugs expose the barrel 
as a metal ring around the end of the insulating 
cover. Grab it wrong, touch the chassis, plug it 
in, and you WILL get kicked if it's a TS loop 
plug.  100 to 200V loop voltage has quite a kick!

73,
Bill, K9GWT


At 10:55 PM 2/16/2009 -0500, eugene at hertzmail.com wrote:
>Content-class: urn:content-classes:message
>Content-Type: multipart/alternative;
>         boundary="----_=_NextPart_001_01C990B3.9C899E5F"
>
>Hi Don, I must admit I was really tempted to 
>keep my TS jacks because I am rather lazy. But 
>then I realized that one misplaced little (my 
>kids’) finger with a loop supply on and that 
>wouldn’t be safe.  Even though the sleeves are 
>electrically isolated on my panel, I still envisioned a finger and a shock.
>
>It would seem to make some sense so I am quite 
>interested to hear the about the norm used on loop jacks.
>
>So I’ve decided to bite the rather large bullet 
>and wire up a whole bunch of TRS jacks in place. 
>Now, if I could only figure out the correct 
>wiring! I’m sure I’ll figure it out hihi!
>
>Thanks
>Eugene
>
>
>
>----------
>From: Don Robert House [mailto:Packard42 at gmail.com]
>Sent: Monday, February 16, 2009 10:37 PM
>To: eugene at hertzmail.com
>Cc: greenkeys at mailman.qth.net
>Subject: Re: [GreenKeys] jackfields
>
>NORMALLY the TRS plugs and jacks are used for 
>audio signals where the TS plugs and jacks are 
>used for 62 milliamp current loops.
>
>Don
>K9TTY
>
>
>On 16 Feb 2009, at 7:01 PM, 
><<mailto:eugene at hertzmail.com>eugene at hertzmail.com> wrote:
>
>
>Hi. I’ve been wiring up a jackfield and was 
>wondering. Would typical tty devices using ¼” 
>plugs use TS or TRS plugs? I happen to have TRS 
>on my 2 machines, but I just wired up the 
>jackfield using TS (shorting) jacks! So right now I have to fix something.
>
>Thanks
>PS if this message gets through, Gil I sent you 
>two emails this morning. Just wondering if you got them. thanks
>
>
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