[Info-vax] retro VMS hardware

[George Cook]

In article <76f4d90c-0d73-4cc5-9ebe-846fc526588c at o35g2000vbi.googlegroups.com>, H Vlems <hvlems at freenet.de> writes:
> On Sep 26, 2:15=A0am, "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 maki=
> ng
>> >> the hole for the "vampire tap". =A0I never installed any thick-wire
>> >> Ethernet myself and only saw it done once. =A0Thinwire was a bit more
>> >> convenient and UTP was right around the corner!
>>
>> > No jig. =A0The clamp part goes over the cable first, and is
>> > tightened with the appropriate wrench. =A0That also includes
>> > two replacable pins that grip through the outer insulation
>> > and into the shield. =A0Using two allows detecting collisions
>> > while sending. =A0(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. =A0The 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.

The history as far as I can tell (the SOC history is confusing):

  H4000 early revs needed a jig and drill

  H4000 later revs (e.g. D1) needed the tapping tool

  The H4000-BA had heartbeat disabled and needed the tapping tool

  H4005 had a configurable heartbeat and needed the tapping tool 

I never saw an early rev H4000.


George Cook
WVNET