Distributing Frame._ The intermediate
distributing board was invented to meet these conditions of unequal
traffic upon lines and of variations in traffic with changes of seasons
and of charges. The intermediate distributing board enables a line to
retain its number and its position in the multiple, but to keep its
answering jack and lamp signal in any desired position. If a flat-rate
subscriber changes to a message rate, his line may be moved to a
message-rate position and be answered, in company with others like it,
by an operator serving many more lines than she could serve if all of
them were flat rate.

=Methods of Traffic Study.= The best way to learn traffic facts for the
purposes of designing and operating equipment is to conduct systematic
series of observations in all exchanges; to record them in company with
all related facts; and to compare them from time to time, recording the
results of the comparisons. Then when it is required to solve a new
problem, the traffic data will enable the probable future conditions to
be known with as great exactness as is possible in studies with relation
to transportation or any other human activity.

TABLE XIII

Calling Rates

+-------------------------+-------------------------------+
| | CALLS PER DAY WITH DIFFERENT |
| KIND OF SERVICE | METHODS OF CHARGE |
| +-------------+-----------------+
| | FLAT RATE | MESSAGE RATE |
+-------------------------+-------------+-----------------+
|Residence | 8 | 4 |
|Business | 12 to 20 | 8 to 14 |
|Private Exchange Trunk | 40 | 25 |
|Hotel Exchange Trunk | 50 | 30 |
|Apartment House Trunk | 30 | 18 |
+-------------------------+-------------+-----------------+

There are three general ways of observing traffic. A record of
originating calls is known as a "peg count," because the counting
formerly was done by moving a peg from place to place in a series of
holes. The simplest exact way is to provide each operator with a small
mechanical counter, the key of which she can depress once for each call
to be counted. A second way is to determine a ratio which exists, for
the particular time and place, between the number of calls in a given
period and the average number of cord ci