[ih] ARPA initial IMP-IMP line speed

Stephen Casner casner at acm.org
Tue Feb 24 14:59:24 PST 2004


On Tue, 24 Feb 2004, Toru Nohzawa , wrote:

> My point is IMP-IMP fact.
> I thought there must be some people who handled the IMPs
> and they must know the fact.
>
> If early ARPAnet used the multiplexed or wideband modem for
> IMP-IMP communication, it might be new news to many people
> and it should be described on the internet history.

I do not know details of the modems, but I remember the large cabinet
that contained them.  This was at ISI from 1973 onward.

BBN Report 1822, "Interface Message Processor: Specifications for the
Interconnection of a Host and an IMP", shows a picture of that cabinet
on page 1-3 and states the dimensions as 68-1/8" x 28" x 28".  That
document does not describe the modems that connect the IMP to the
"wideband communication lines" that interconnect the IMPs.

                                                        -- Steve




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