[ih] Arpanet physical connectors
jack at 3kitty.org
Thu Jul 23 11:54:56 PDT 2020
Yeah, lines were a problem everywhere too. I was peripherally involved
in the 80s with an ARPANET clone that we deployed and then ran for a big
international corporation. They tended to need IMPs and lines at sites
in unusual places which made it even harder to get them. I remember
one time a line was needed in some obscure country (one of the tiny
countries in South America IIRC), and the quoted delivery time was
something like 2 years. Even that was a "maybe".
As we engineers mused about alternatives like satellite circuits, the
corporation solved the problem as big corporations do. They simply
bought the country's PTT operation. The line we had ordered was
installed a few weeks later.
It got better though. I remember at some point we created a portable
package (basically a PC, modem, and IMP, which were much smaller by
then) that a salesperson could take on a sales call. A live demo was
performed - e.g., by simply unplugging the phone line from the phone on
the manager's desk, plugging it into the IMP/modem, and linking the node
in as part of our demo network back in Cambridge. Took literally a few
minutes, and probably helped sell a few ARPANET clones during the 80s.
IMHO, part of the History of the Internet involves the History of the
Mundane - like connectors and lines.
On 7/23/20 10:15 AM, Steve Crocker wrote:
> Equal pain on the long distance lines. They had to be ordered through
> AT&T Long Lines. Standard delivery time was nine months. In one case
> we ordered lines into and out of Boulder, CO. And then the intended
> site balked and said they didn't want to be connected. We wound up
> putting a TIP into a Dept of Commerce office building in Boulder.
> On Thu, Jul 23, 2020 at 1:00 PM Jack Haverty via Internet-history
> <internet-history at elists.isoc.org
> <mailto:internet-history at elists.isoc.org>> wrote:
> On 7/23/20 8:53 AM, Noel Chiappa via Internet-history wrote:
> > To start with DH (by far and away the most common), IMPs had a
> specified round
> > 'female' plug (a mil-spec connecter, available from AMP - like
> the one in the
> > URL Carsten provided - I think the axact part number is in the
> > mounted on the back of the IMP somewhere.
> I remember these connectors well, because of a strange experience
> I had
> involving them.
> They were big, sturdy, heavy, expensive military-grade connectors. I
> don't remember the part number though. Computer interconnecting
> in that era were often large and unwieldy. E.g., the PDP-10 bus
> to interconnect processor, memories, storage cabinets et al were huge,
> and quite expensive.
> At one point in the 80s, I was in charge of a contract to build and
> deliver some equipment using the same connectors, in order to be
> compatible with the IMPs. We had a tight schedule, with the contract
> requiring delivery of the first units 12 months after signing the
> Not expected to be a problem. Except..... we quickly discovered
> those particular connectors were readily available through the usual
> channels --- with a lead time of 60 weeks to delivery!
> Apparently such
> military-grade connectors are only built when needed, and unless we
> ordered 10,000 or so they wouldn't schedule a special manufacturing
> run. We should have ordered them before we submitted the
> proposal I guess.
> So much easier these days. After all there's not all that many
> different flavors of USB physical connectors! All available with
> one or
> two day delivery too.
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