I appreciate the approach Olin took on this.   When I read the original
post, I began to worry that all my designs that use an RJ-12 connector were
somehow flawed.   It took me about 15 minutes of thinking about the jack to
decide my fears were unfounded and that I had temporarily allowed the OP to
anchor me with a negative opinion of the jack.

On 10/25/06, Olin Lathrop <olin_piclist@embedinc.com> wrote:
>
> Rolf wrote:
> > For the record, I figured Olin's pedantic reply about his ICD2 not
> > having an RJ12 plug was worth investigating, and it appears he is right.
> >
> > ICD2 s do NOT have RJ12 jacks. There apparently is no such thing
> > specified. An RJ11 jack is a 6p2c modular plug, an RJ14 is 6p4c, and an
> > RJ25 is 6p6c.
>
> This is not what I was trying to point out.  I said I don't have a ICD2
> with
> a "ridiculous RJ12 jack" as the OP asked about.  Mine all have regular and
> quite reasonable RJ12 jacks.
>
> I didn't like the way the OP was asking for help and at the same time
> putting words in anyone's mouth that might help him.  His question was a
> lot
> like "Have you stopped beating your wife?".  Anyone responding to the OP's
> question would be implicitly agreeing that the ICD2 connector is
> "ridiculous" and that "everyone knows" that.  I thought that was arrogant
> and a particularly obnoxious way to make a point, so I responded to his
> post
> in a way that was litterally correct but otherwise useless.
>
> If the OP thought a RJ-12 was the wrong choice for the ICD2 connector he
> should have stated that as his opinion and provided some support for his
> argument, instead of just calling it "ridiculous" and implying everyone
> agrees with that.
>
> For the record, I think RJ-12 was a reasonable choice.  It is quick to
> connect and disconnect, locks with a positive feel, can't be plugged in
> backwards, cheap, and widely available.  These connectors have proven to
> work well in nearly 30 years of telephone use.
>
> The one part of the design I don't like is the pinout.  PGC and PGD are
> next
> to each other.  This invites crosstalk, and I've presonally seen it
> happen.
> At the time of the design, Microchip was vaguely planning the last pin for
> PGM, but that was never implemented.  In hindsight it would have been much
> better to separate PGC and PGD with a extra ground wire.  All my
> programmers
> have a RJ-12 jack for compatibility, but also a 6 pin header and/or pads
> with the extra ground line between PGC and PGD.  For programmers built
> into
> fixtures, I always recommend the 6 pin interface be used instead of the
> RJ-12, but not because there is anything wrong with a RJ-12 jack.
>
>
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