The Bennington evening banner. (Bennington, Vt.) 19??-1961, 1918-12-13
NE VI INVENTION
n AIDS CAPACITY
FOR messages
Theodore n. Vail Announces De
velopment OF Multiplex System
LONG DISTANCE SERVICE
over Single Pair Of Wires Five TeIe.
phone Conversations Are Stimuli
taneously Operated.

Washington, Dec. Postmaster
General Burleson today made public
a letter from Theodore n. Vail, presi-
dent Of the American Telegraph and
Telephone Company announcing the
invention and development by the
technical staff Of the Bell system OF
"a practical system OF mutiplex tele.
phonoy and telegraphy by the use of
which ii is now possible to increase
many fold the message carrying ca
pacity OF long telephone and telegraph
wires.
With this new SYSTEM said AIr
Wallis letter, -four te phone conyer-
sations over one pair Of wires are
simultaneously csrried on, in addition
to the telephone conversation proyid-
ed by The ordinary methods Thus
over a single pair OF wires total of
FIVE telephone conversations are sim
ultaneously operated each giving sery
ice as good as that provided by the
circuit working in the ordinary way.
"a number OF years ago, we develop
ed the phantom circuit arrangement
by which three telephone circuits are
obtained from two pairs of wires
Now by our multiplex methods. we
are enabled TO obtain five telephone
circuits over one pair OF wires, that
Is ten simultaneous telephone con.
versations from the two pairs OF
wires which formerly could be used
for the only three simultaneous iele
phone conversations.
In telegraphy as we'll as in tele
phony, sensational results have been
attained by the new system BY com
hining two telegraph wires into a me
/ ta'lic circuit of the type used for the
phones, working b. applying our new
apparatus and melRods to this metal
ic circuit wa aAvA o1 rm selg .in
creased the capacity Of the wires FOL
elegTaph messages without. IA ans
way. impairiug the quality Of tele
Grams working.
The nature Of these development.
Is such that IL desired wires may b,
used partly for telephone and partl,
sor telegraph. A pair of wires IL
available either for FIVE simultaneous
telephone conversations or for fort,
iimultaneous telegraph messages oi
'artly for one and partly for the 9th
~.
From The nature Of the apparatus
and the methods employed the system
IS not practically advantageous oi
short lines. either telephone or tele
graph. On long lines. its application
will be extended Immediately. but it
Introduction must necessarily be grad
1al on account OF the nature of the al
naraius required and the rearrange
nent and adaptation OF the lines then
elves and their associated apparatu,
o the new methods of working 10 +
not too much to characterize thi
lew system as marking an epoch il
he development of long distance tele
)hony and telegraDhy"
Mr. Vail said that an installation O
he multiplex telephone system he
wecn Baltimore and Pittsburgh ha
leen in service for more than a mont
On Monday OF this week" he sale
accompanied by q party Of distin.
ilshcd government and telqphon
md telegraph officials made an IL
| 'pection of the system az Baltimor.
nd a test OF the service provided hi
ween Baltimore and Pittsburgh. A
I the party were delighted with
uccessful working of the new systei
nd the evident skill which had bee
hown in developing it,