| 17 | 37 | 57 | 77 | 97 |
| Brown-White | 18 | 38 | 58 | 78 | 98 |
| Brown-Slate | 19 | 39 | 59 | 79 | 99 |
| Slate-White | 20 | 40 | 60 | 80 | 100 |
+---------------+-------+-------+-------+-----------+-------------+

The numerals represent the pair numbers in the cable.

The wires of spare pairs usually are designated by solid red
with white mate for first spare pair, and solid black with
white mate for second spare pair. Individual spare wires
usually are colored red-white for first individual spare, and
black-white for second individual spare.

CHAPTER XXVIII

FUNDAMENTAL CONSIDERATIONS OF AUTOMATIC SYSTEMS

=Definition.= The term automatic, as applied to telephone systems, has
come to refer to those systems in which machines at the central office,
under the guidance of the subscribers, do the work that is done by
operators in manual systems. In all automatic telephone systems, the
work of connecting and disconnecting the lines, of ringing the called
subscriber, even though he must be selected from among those on a party
line, of refusing to connect with a line that is already in use, and
informing the calling subscriber that such line is busy, of making
connections to trunk lines and through them to lines in other offices
and doing the same sort of things there, of counting and recording the
successful calls made by a subscriber, rejecting the unsuccessful, and
nearly all the thousand and one other acts necessary in telephone
service, are performed without the presence of any guiding intelligence
at the central office.

The fundamental object of the automatic system is to do away with the
central-office operator. In order that each subscriber may control the
making of his own connections there is added to his station equipment a
call transmitting device by the manipulation of which he causes the
central-office mechanisms to establish the connections he desires.

We think that the automatic system is one of the most astonishing
developments of human ingenuity. The workers in this development are
worthy of particular notice. From occupying a position in popular regard
in common with long-haired men and short-haired women they have recently
appeared as sane, reasonable men with the courage of their convictions
and, better yet, with the ability to ma