336 
The N.Z. Journal of Science and Technology. 
[Nov. 
the order clerk who, upon receiving the orders, enters them in shop form 
and distributes them throughout the works so that they are received in 
the correct department and executed in accordance with the customers’ 
wishes. 
The first machine to move after the impulses have been sent into the 
register set (in fact, this machine starts to move as soon as the first digit 
has been sent into the register set) is the group-switch which was spoken 
of before. You will notice a small shaft at the left-hand side of this 
mechanism, in which there are a number of pins projecting radially and in 
a spiral relationship to each other. This shaft has at the bottom of it a 
toothed wheel, or interrupter, on which there are ten notches, and the 
shaft now revolves to the extent of so-many notches, depending upon the 
number stored up in the thousands 
register, this being the register which 
recorded the number of the first digit 
sent in by the subscriber. When this 
shaft, or trip-spindle, has revolved 
this predetermined number of notches 
it is automatically stopped by the 
thousands register being in its home 
or normal position, as this register 
has been stepped home in electrical 
synchronism with the forward move¬ 
ment of the trip-spindle. In this 
predetermined position of the trip- 
spindle, one, and only one, of the radial 
teeth is projecting in the path of the 
hard rubber portions of the brush- 
carriage, or larger revolving member 
on the group-switch, and at this time 
the circuit is so arranged that the 
brush-carriage starts to revolve, and 
when it passes the line of radial pins 
on^ the trip-spindle one set of brushes 
is released, and, as the brush-carriage 
continues to revolve, this one predeter¬ 
mined set is dragged across the face 
of the terminals on the terminal arc. 
This terminal arc is divided into ten 
levels corresponding to the thousands, 
each level consisting of a series of sets of three terminals each. These 
sets of three terminals represent trunks from this group-switch to the 
switches of the ten sets of thousands, and as the brush-carriage drags 
one set of brushes over one level of terminals it makes an electrical 
test to determine which one of these sets is disengaged, and, having run 
on to a disengaged set, the mechanism stops revolving, and connection 
is now completed from the subscriber’s telephone, through the line-finder, 
through the group-switch, on to a trunk leading into the desired group 
of 1,000 lines. This trunk terminates in a second group - switch, 
which is identical in construction and operation with the group-switch 
just described, and this second group-switch is connected with the hundreds 
register in the register set, and a certain level is selected by the trip-spindle, 
depending upon the setting of the hundreds register, and subsequently a 
Fig. 5.—Register. 
