Re: 707 : How did it get its name ?

Date:         20 Jan 98 01:29:54 
From: (Seán Emmett Crumley)
Organization: D.C. Public Library
References:   1 2 3 4
Next article
View raw article
  or MIME structure

In article <airliners.1998.59@ohare.Chicago.COM>, (C. Marin Faure) wrote:
> Everything about this post is right except my statement that the 707 is
> actually called the 700 on the Type Certificate.  It's not.  The numbers
> that ARE different on the Type Certificate from the numbers in common
> usage are the dash-numbers.  The 707-120 is officially called a 707-100,
> while the 707-320 is officially called a 707-300.  Sorry for the error.

Okay...I'll ask:
If the type certificate officially called the 707s -100s and -300s where
did the    apellation of -120 and -320 come from?