Daily Kennebec journal. [microfilm reel] (Augusta, Me.) 1870-1975, 1901-11-19
Russell s Weston, 100 % %.%a St. Augusta, Maine.

lr"rSation II the called lineis busy. upon
| listening in his receiver. he hears a
| huZzing sound notifying him of this
| fact. Calling requires one second or less
for each number.
| The operation of the calling device is
| very simple and will be explained be-
, low.
| The subscribers lines entering TIE
| Exchange terminate in the usual light
! ming arresters and heat coils and pass
| thence through a distributing rack to q
bank Of selectors. Each line is coa-
nee red with one OF the SelectO.' ma
chimes. which occupies Il space of
about 1our by five inches in pla1 and
| ten inches high. The selector switch
| cCi sIstS of 100 contacts. rarSe.i in ten
rows &C ten each, mounted on A semi
circular structure. occupying the axis
of which i /" vertical rod adapted to
b. moved vertically and rotated. Bet
ter to explain the system in use the
method of connecting an exchange of
100 or less subscribers will be described
first. In this case each subscribers
Sclector Is connected with all the
Others. Tie first movement Of the
calling subscribers step by step select
ing disc. which he operates in calling.
picks out the ten" and the next move
nent the unit" this being Very sim
ply accomplished by sending in the
first seective signal over one side :.
lis two-wire circuit and the ode"
signal over the other side in Eoth
cnscs thu. ground being used ~ re-
turn for the signaling currea.. AS
sumo That tie subscriber cal!.l IS NJ
o. The first movement to the figurn G
on the calling disc will result in step
ping the vertical rod of his selector up
six steps. or 50 that the wiping contact
arm which it carries is opposite the
beginning of the sixth row of contacts.
The second movement to 3 will reVoive
the selector switch three steps. leaving
tire wipins contact on the third point
on the sixth row and thus connecting
the subscriber With telephone Ma. SO.
This connection being accomplished.
the caller pushes a button 10 ring the
bell of the called subscriber and con-
yerSation proceeds. Should the latter.
however be already connected with
some other telephone than by simple
relay mechanism an interrupted bat
terry current is thrown on the line OF
the calling subscriber. producing an
unmistakable audible signal which in
forms him that the called line is busy.
When the conversation is finished
hanging up the telephone OF the caller
sends current over both his lines ana
releases the step by step mechanism so
tina; his Selector on the SWITCHBOARD
goes back to its initial position ready
fo. another call.
The extension Of this system To an eN-
change having between 100 and lr" SUD
scribers is exceedingly simple. In TINS
cas-. the first signal made instead OF Sc
ractiug the first digit of the called number
directly connects the calling line to one OF
ION or moro trunk lines, all of which lead
10 eroups of instruments containing To-
i'm each For example If tn" nunoef
called is $40 the first signal sent IN VIII
pick llp one Of ten lines leading TO the
fifth group of 100 and the next Two Sis-
mails will select from this group the teic-
phone number ii in it giving the desired
can. For exchanges to have between l"o
,nd ia nn subscribers as in Fall River. the
first two signals pick out first the th"h-
sand yroup then the hundred group III
which the called number is found
II has been found in practice that ten
of these trunk lines are sufficient Tor eac"
100 Subscribers as the apparatus Is auto
maticallv selectivc and proceeds 10 plch
ont , trunk line which is not busy. pass
i'm, over those which are occupied without
stonninc If none Of the ten lines is IN
~, tbu first signal sent in by a calling
lines If this happens to be in use the
instrument automatically proceeds 10 'hc
second one. and on until one line 81
the group not occupied IS picked out III
the rare instance where all ten are pus!
the result is that the calling subscriber
gets the busy signal.
Currant for operating all the signaling
mechanism and the bell ringing is gem
Grated nj the central exchange in a pat
,erv If thirty storage cells, which are
charged at convenient intervals through
a batterv-charginS motor-dynamo from
the local electricity supply mains. For
working the selector signals, direct cur
rent of about Of ampere is used while i"r
hell ringing an alternating current is pro-
vided bv the usual motor generator set.
To att.mut a detailed description OF the
numerous ingenious points of this sys-
fem would carry this article beyond Its
limits and reference can be made here
only 10 :, few Of the salient features OF
the system.
II viii h. noted that all Of the contacts
cmploved except the relay used in clos
ing the bell-ringins circuit through the
| called Subscriber line. are Of the wipe
| contract type. thus ensuring good con-
| tact and minimizing the ill effects of dust
and dirt. No conversation is ever carried
| on through an abutting contact. ali OF the
contacts in the talking circuit being On
| the wine variety. Only two wires are run
! to each subscriber. and the apparatus for
| calling and signaling is OF the central
energy type. all of the current generating
and converting devices being at the eN-
change where they are under Supervision.
The anparatus at the subscribers station
is no larger than that employed by Other
| telephone systems
! The advantages claimed for this auto
matte system are numerous and very i'm
portant Perhaps foremost is the ra pidity