[Info-vax] retro VMS hardware

[H Vlems]

On Sep 26, 2:15 am, "Richard B. Gilbert" <rgilber... at comcast.net>
wrote:
> glen herrmannsfeldt wrote:
> > Richard B. Gilbert <rgilber... at comcast.net> wrote:
>
> >> ISTR a "jig" that fastened on to the cable and guided a drill bit making
> >> the hole for the "vampire tap".  I never installed any thick-wire
> >> Ethernet myself and only saw it done once.  Thinwire was a bit more
> >> convenient and UTP was right around the corner!
>
> > No jig.  The clamp part goes over the cable first, and is
> > tightened with the appropriate wrench.  That also includes
> > two replacable pins that grip through the outer insulation
> > and into the shield.  Using two allows detecting collisions
> > while sending.  (Even better would be with two center
> > conductor taps, but that seems not to be needed.)
>
> > Then the drill goes through the hole in the clamp such that the
> > hole has the right depth and position.  The other end of the
> > drill has the wrench to screw in and tighten the actual tap.
> > There is a cover to put over it until a transceiver is installed.
>
> > -- glen
>
> Seehttp://dictionary.reference.com/browse/jig
>
> I think it's correct to describe the clamp as a jig since it functions
> as one.- Hide quoted text -
>
> - Show quoted text -

ISTR there are two H4000 models, the first model required a jig and
and a drill to get it installed. The other had the same clamp as the
H4005.
The first model was not fit for use with H4005's and thinwire kit,
there's a heartbeat issue that preventsproper operation in mixed
configurations.
Mixed meaning combining 10base5 and 10base2 gear, like fitting a DESPR
to a 10base5 backbone. There is a hardware fix for the newer H4000
(which makes it an H4000-AB IIRC). It involves removing one small
capacitor. The H4005 has this fixed too.
Hans