New-York tribune., 1918-12-13
New Invention
ReyOlutiOnizes
Wire Service
Five Telephone or Forty
Telegraph Messages on
One Circuit Is Possible
One System Now Working
Theodore N. Vail Reports
Sensational Results of
Multiplex Method Tests

WASHINGTON, Dec 12.-Postmaster
General Burleson to-day made public
q letter from Theodore N. Vail, presi-
dent of the American Telegraph and
Telephone Company. announcing the
invention and development by the tech
nical staff of the Bell system of "a
practical system of multiplex tele-
phony and telegraphy by the use of
which it Is now possible to increase
.manyfold the message carrying ca
pacity of long distance telephone and
telegraph wires"
with this new SYSTEM" said Mr..
Wallis letter, -four telephone CONVEX
.satlons over one pair of wires are
simultaneously carried on, in addition
& to the telephone conversation provided
by the ordinary methods. Thus over
single pair of wires a total of five
telephone conversations are simultane-
ously operated, each giving service as
good as that provided by the circuit
working in the ordinary way.
"A number of years ago we devel-
'-oped the phantom circuit arrangement
by which three telephone circuits are
obtained from two pairs of wires Now
by our multipleX methods wetare en-
abled to obtain five telephone circuits
over one pair of wires; that is, ten
simultaneous telephone conversations
from two pairs of wires which former
ly could be used for only three simul-
taneous telephone conversations.
'ln telegraphy as we'll as in tele-
phony, sensational results have been
attained by the new system. BY COM
'bining two telegraph wires into a
metallic circuit of the type used for
telephone working and by applying our
new apparatus and methods to this
metallic circuit we have enormously
Increased the capacity of the wires for
~ telegraph messages without in any way
impairirg the quality of telegraph
working.
The nature of these developments
is such that, if desired, wires may be
used partly for telephone and partly
for telegraph. A pair of wires is avail
able either for five simultaneous tele-
phone conversations or for forty stimuli
taneous telegraph messages, or partly
-, for one and partly for the other.
From the nature of the apparatus
and the methods employed the system
is not practically advantageous on short
& lines, either telephone or telegraph. On
long lines its application will be ex-
tended Immediately, but its introduc-
tion must necessarily be gradual on &C
required and the Encouragement and
adaptation of the lines themselves and
their associated apparatus to the new
methods of working.
"It is not too much to characterize
this new system as marking an epoch
in the development of long distance
telephony and telegraphy."
Mr. Vail said that an installation of
the multiplex telephone system be-
tween Baltimore and Pittsburgh had
been in service for more than a month.
"On Monday of this week." he said
guished government and t telephone a'a1,,] and
telegraph officials, I made an inspec-
..tion of the system of Baltimore and a
test of the service provided between
Baltimore and Pittsburgh. All of the
party were delighted with the success
ful working OF the new system and the
evident skill which had been shown in
deyelOping it."