rcuits in use. Knowing this
ratio, the cord circuits can be counted, the ratio applied, and the
probable total known. The third method, which is applicable to offices
having service meters on all lines, is to associate one master meter per
position or group of lines with all the meters of that position or
group, so that each time any service meter of that position is operated,
the master meter will count one unit. This method applies to either
manual or automatic equipments.

=Representative Traffic Data.= For purposes of comparison, the following
are representative facts as to certain traffic conditions.

_Calling Rates._ The number of calls originated per day by different
kinds of lines with different methods of charge are shown in Table XIII.

_Operators' Loads._ The abilities of subscribers' operators to switch
these calls depend on the type of equipment used, on the kind of
management exercised, and on the individual skill of operators. With
manual multiple equipment of the common-battery type, and good
management, the numbers of originating calls per busy hour given in
Table XIV can be handled by an average operator. The number of calls per
operator per busy hour depends upon the amount of trunking to other
offices which that operator is required to do. In a small city, for
example, where all the lines are handled by one switchboard, there is no
local switching problem except to complete the connection in the
multiple before each position. In a large city, where wire economy and
mechanical considerations compel the lines to be handled by a number of
offices with manual equipment, some portion of the total originating
load of each office must be trunked to others. Table XIV shows that an
increase of 90 per cent in the amount of out-trunking has decreased the
operator's ability to less than 70 per cent of the possible maximum.

TABLE XIV

Effect of Out-Trunking on Operator's Capacity

+----------------------------+---------------------------------------+
|PER CENT ORIGINATING CALLS | CAPACITY OF SUBSCRIBERS' OPERATOR'S |
|TRUNKED TO OTHER OFFICES | POSITION IN CALLS PER BUSY HOUR |
+----------------------------+---------------------------------------+
| 0 | 240 |
| 10 | 230 |
| 30 | 200 |
| 50