396 Telephone Systems of the Continent of Europe 



freed and may be withdrawn. Fig. 139 shows this arrangement. 

 When it is desired to withdraw one of the lower strips it is 

 necessary to lift the superincumbent layers of cables on a steel 

 stirrup or frame. 



All modern boards are provided with means for distributing 

 the work with some approach to equality amongst the operators, 

 for when this cannot be done it frequently happens that several 

 very busy subscribers are grouped together on the board and 

 provide more work for the operator of that section than she can 

 properly attend to, while her neighbour may be almost idle owing 

 to the presence on her section of many quiet subscribers. At 

 Zurich the indicators and the corresponding local jacks are 

 numbered i to 119 in each working section throughout the board, 



FIG 139 



while the repeat jacks are numbered o to 5,399, being the list 

 numbers of the subscribers. When a drop falls, the operator plugs 

 into the corresponding local jack, and having ascertained the 

 number wanted, completes the connection through the repeat 

 jack which bears it. She has no occasion to know the list number 

 of the calling subscriber unless the connection demanded cannot 

 be given at once, when it must be asked for in order that he may 

 be rung up later. In a busy exchange this may, however, become 

 an important point, and it would be an improvement to add a 

 second number (which might be movable) to the indicator show- 

 ing the true list number of the caller. The equalisation of work 

 is effected by an intermediate field in the following manner. The 

 repeat jacks of each group of subscribers are connected in parallel 



