The Minneapolis journal. [volume] (Minneapolis, Minn.) 1888-1939, 1902-01-11
AUTOMATIC PHONES
How Time Is Saved for the Tele-
phone Users.
DEVICE USED AT FALL RIVER

The Business of 600 Subscribers In
| Handled in the Main by
Machinery.
| Electrical Review.
At Fall River, Mass, known the world
over as one of the busiest and most i'm
portant OF the New England manufactur-
| ing town. there is now in successful oper-
alton an automatic telephone exchange.
| using the Stronger system and handling
| the business OF nearly 600 subscribers.
| The exchange was built by local COM
pany and represents the most modern
and complete installation of aut omatic
! telephones in the United States.
! The difference between automatic ex-
changes and manually operated exchanges
consists in the entire suppression, in the
former. OF the services of a third party in
| making connection. The system at Fall
River comprises an exchange, centrally
located in small brick building and a
! full metallic system of circuits to the
subscribers distributed over large por-
| tion of the city and it's suburbs. The wir-
Ing from the exchange to these sub
| scr1bers is carried out underground in
! twisted pair cables Of the conference"
standard. In the outlying districts Of the
city the lines are overhead, Of the usual
construction, cables being carried on
| run thence by aerial wires to the sub
| scribers' premises. In it's external details
the wiring for this exchange Is precisely
similar to that for any metallic circuit ex-
change system using a manual switch
| board; the difference is found in the
subscribers instruments and in the ex-
change itself
The subscribers station contains, beside
| the usual bells, transmitter, induction
coil, battery and receiver, the selective
calling apparatus, which is mounted in a
box about the size of the usual telephone
magnetic On the front of this box is a
disk OF metal, having along the edge on
from to o. BY inserting the finger in one
OF these holes the disk may be turned,
stop placed at the lower part limiting the
distance to which 1t may be turned with
the hnger In any given hole. To call
number the subscriber first removes the
receiver from it's hook and inserting his
finger In turn in the holes Of the proper
number, turns the disk until his finger is
stopped at the bottom, then releases it,
and lets 1t go back to its starting position
Having turned up the proper numbers in
this way he presses a button which rings
| the called subscribers bell and if the
| called line is not busy proceeds with his
conversation. II the called line is busy
upon listening In his receiver he hears a
buzzing sound notifying him of this fact
Calling requires one second or less for
each number. .--~lr ~, r. .,.
The subscribers lines entering the ex-
| change terminate in the usual lightning
arresters and heat coils and pass thence
! through a distributing rack, to a bank iof
| selectors. Each line Is connected with
| one of the selector machines, which occu-
pies sDace Of about four by five inches
! In plan and ten inches high. The Sc
| lectOr switch consists Of 100 contacts,
| ranged IN ten rows of ten each, mounted
on a seml-circular structure, occupying
the axis Of which is a vertical rod adapt
ed to be moved vertically and rotated.
| Better 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 selector is
connected with all the others. The first
movement of the calling subscribers step
| by step selecting disk, which he operates
in calling, picks out the stem" and the
next movement the ''unit," this being
very simply accomplished by sending in
the first selective signal over one side OF
his two-wire circuit and the other sig
| nal over the other side, in both cases the
| ground being used as return for the
signaling current. Assume that the sub
scriber called is No. 60. The first move
ment to the figure 6 on the calling disk
| will result in stepping the vertical rod
l
Wip1ng contact arm which 1t carries Is op-
| posite the beginning of the sixth row OF
| contacts. The second movement to {
! will revolve the selector switch three
steps, leaving the wiptng contact on the
third point on the sixth row and thus con-
Meeting the subscriber with telephone No
| SO. This connection being accomplished
the caller pushes button to ring the bell
| OF the called subscriber and conversation
proceeds. Should the latter, however
| be already connected with some other
telephone, then by simple relay mechan-
! ism an Interrupted battery circuit is
| thrown on the line of the calling sub
scriber producing an unmistakable audible
| signal which informs 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
and releases the step by step mechanism
/ so that his selector on the switchboard
goes back to its initial position ready fo1
another call.
The extension of this system to an ex-
change having between 100 and 1000 sub
scribers is exceedingly simple. In this
case the first signal made instead Of Sc
lecting the first digit of the called num-
Der, directly connects the calling line to
one of ten or more trunk lines, all Of which
lead to groups of instruments containing
| 100 in each. For example, if the mum
Der called is SAG, the first signal sent in
will pick out one of ten lines leading to
| the fifth group Of 100 and the next two
! signals will select from this group the
telephone number As in it, giving the de-
sired call. For exchanges to have be-
| tween 1000 and 10000 subscribers, as in
| Fall River, the first two signals pick out
first the thousand group, then the hun
dred group in which the called number is
| found.
1t has been found in practice that ten of
! these trunk lines are sufficient for each
| 100 subscribers. as the apparatus is au-
| toma tically selective and proceeds to pick
| out trunk line which is not busy, pass
| ing over those which are occupied without
| stopping. If none of the ten lines is in
use, the first signal sent in by calling
subscriber will stop on the first of the
lines. If this happens to be in use, the
instrument automatically proceeds to the
second one. and SO on, until one line OF
the group not occupied is picked out. In
the rare instance where all ten are busy
the result is simply that the calling sub
scriber gets the busy signal.
Current for operating all Of the sig
Mailing mechanism and the bell ringing
is generated at the central exchange in 8
battery Of thirty storage cells, which are
charged at convenient intervals through
a battery charging motor-dynamo from
the local electric supply mains.
The advantages claimed for the auto
/ matte system are numerous and very i'm