Networks

Until ten years ago, the telecommunications and computer
industries were almost entirely separate. Shortly they will be almost
completely fused. Most of today's hackers operate largely in
ignorance of what goes on in the lines and switching centres between
the computer they own and the computer they wish to access.
Increasingly, dedicated hackers are having to acquire knowledge and
experience of data networks, a task made more interesting, but not
easier, by the fact that the world's leading telecommunications
organisations are pushing through an unprecedented rate of
innovation, both technical and commercial. Apart from purely local
lowspeed working, computer communications are now almost
exclusively found on separate high-speed data networks, separate that
is from the two traditional telecommunications systems telegraphy and
telephone. Telex lines operate typically at 50 or 75 baud with an
upper limit of 110 baud.
The highest efficient speed for telephone-line-based data is 1200
baud. All of these are pitifully slow compared with the internal
speed of even the most sluggish computer. When system designers first
came to evaluate what sort of facilities and performance would be
needed for data communications, it became obvious that relatively few
lessons would be drawn from the solutions already worked out in voice
communications.