[ih] Arpanet line speed

[dave.walden.family at gmail.com]

See the text immediately below Figure 1 on the second page at 
   http://walden-family.com/public/1970-imp-afips.pdf
probably drafted by Bob Kahn.

Sent from my iPad

On Jan 18, 2017, at 9:57 AM, Vint Cerf <vint at google.com> wrote:

> Noel, wasn't it GTE (General Telephone and Electric)?
> 
> v
> 
> 
> On Wed, Jan 18, 2017 at 9:29 AM, Noel Chiappa <jnc at mercury.lcs.mit.edu> wrote:
>     > From: Paul Ruizendaal
> 
>     > - if the modem from the IMP to the Bell System was analog, the best
>     > technology of the time was perhaps 2.4kb/s ... a speed of 50kb/s is not
>     > a multiple of 2.4kb/s, and it would have required 21 parallel lines
> 
> If you read the 303 manual, it's clear that i) the signal between a pair of
> 303 modems was analog, not digital, and ii) there was a single line, with a
> wide enough bandpass to carry signals of high enough frequency to carry that
> bit rate - it didn't glue together a bunch of slower lines.
> 
>     > if the modem from the IMP to the Bell System was digital, it would most
>     > likely have used a single channel of a T1 connection
> 
> The whole T hierarchy was just getting started then (initial deployment in the
> early 1960s), and I'm not sure if it was deployed widely enough to have made
> it possible to lease a T1 line from one coast to another.
> 
> Also, many of these lines would have crossed non-AT+T local phone companies
> (the Bell System did not control all of the US phone system, although some
> people don't realize that). The "History of the ARPANET: The First Decade"
> (which I have previously pointed you at on another list), pg. III-32, says
> "In the case of a circuit from UCLA to RAND ... the service would be procured
> from General Telephone" - GT was the largest independent telephone company in
> the US at that point. It's not clear that those local carriers would have
> supported T1.
> 
> 
> Moral of the story: when doing history, it's bad to make assumptions about
> what was and wasn't possible, and about what did and did not happen. Find
> contemporary documentation.
> 
>         Noel
> _______
> internet-history mailing list
> internet-history at postel.org
> http://mailman.postel.org/mailman/listinfo/internet-history
> Contact list-owner at postel.org for assistance.
> 
> 
> 
> -- 
> New postal address:
> Google
> 1875 Explorer Street, 10th Floor
> Reston, VA 20190
> _______
> internet-history mailing list
> internet-history at postel.org
> http://mailman.postel.org/mailman/listinfo/internet-history
> Contact list-owner at postel.org for assistance.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://elists.isoc.org/pipermail/internet-history/attachments/20170118/a0771f85/attachment.htm>