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Патент USA US2008281

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Ju?y "R6, 1935.
H. HOVLAND
2,®®8,2M
TELEPHONE SYSTEM
Filed April 20, 1954
l2/
TDIFMELRN LMARGINA
2 Sheets-Sheet 1
SVER7.-TEP
//
SR07.TEP
FIG./
MARG/NL
|\
_
By
lNl/ENTOR
H. HUI/LAND
A 7-70 NEV
Jun)’ 16, 1935.
'
H. HOVLAND
TELEPHONE
2,@ ,281'
SYSTEM,
Filed April 20,- 1954
2 Sheets-Sheet 2
‘235234-
FIG.2
2023 0
INVENTOR
'
H. HUI/LAND
ATTOR 5r
Patented July 16, 1935v
2,008,28i
UNITED STATES
.
PATENT OFF ICE
2,008,281
TELEPHQNE SYSTEM
Henry Hovland, Williston Park, N. Y., assignor to
Bell Telephone Laboratories, Incorporated, New
York, N. Y., a corporation of New York
Application April 20, 1934, Serial No. 721,513
9 Claims. (Cl. 179—8.5)
This invention relates to telephone systems and mon line Hill to terminals in one bank of the
particularly to those involving’ party lines line-?nder switch. This line-?nder LF has two
equipped for message register service.
banks and two sets of brushes. The lines of one
Its objects are to secure improvements in the group, including line I00, are connected to ter
\5 identi?cation of a calling station on a party line, minals in one bank (upper) to which the brushes
to guard against the inaccurate charging of calls
made by the different subscribers, to enable a
test of theyidentifying equipment on every call,
and to otherwise improve systems of this kind.
5
H5, H6 and Ill have access; and the lines of
the other group (none shown) are connected to
terminals in the other bank (lower) to which
the brushes I I8, I I9 and I26 have access. When
A feature of the invention is a party-line sys ever a call is originated over a line to which the
tem in which an identi?cation device, such as a line-?nder has access, a ground is connected to
'
20
25
30
space-discharge tube, is provided at one of the the commutator segment corresponding to the
stations, together with means at the central of level in which the terminals of this line are lo
?ce for connecting a source of identi?cation cur cated. This ground connection is controlled by
rent to the line, when a call is made, to deter the single group relay l 1'33 for all of the lines
mine the presence or absence of said tube, and in connected to the terminals of that level of both
which a test is made after the calling party has banks.
replaced his receiver to determine whether or
Since but one set of two sets of brushes has
not said identi?cation device is in operative con access to the terminals of a particular line, the
dition. In this way it is possible ‘to determine the required set of brushes must be rendered effective,
accuracy of the identi?cation test, which assumes to the exclusion of the other set, at or before the
that the tube or other device is in operative con ?nding of the terminals of the calling line. To
dition, since the subsequent test for operative this end the aforementioned group relay is ar
ness is made when all receivers are on the switch ranged to connect the corresponding commu
hooks, at which time it is de?nitely known that tator segment to ground through resistance 5M
the tube is connected in circuit with the line.
if the calling line is connected to terminals in
Another feature is an arrangement in which the upper bank, and to connect the segment di
one of the registers of a two-party line is con rectly to ground if the calling line is connected
nected to the sleeve conductor and the other regis to terminals in the lower bank.
ter to one of the talking conductors, and in which
Fig. 2 shows a trunk circuit T—-l and a ?rst
the latter register is selectively connected to the selector S for extending the connection to a called
line for operation by means of the line relay. station (not shown) through a second selector
Since it is desirable to have the register discon
(not shown) and connector (not shown) in the
nected from the talking conductor during conver well known manner. The trunk circuit T-l is
sation, this is accomplished by holding the line
relay operated to hold open the register circuit.
At the end of conversation, dependent on
which party made the call, either the register
on the sleeve is operated or the line relay is re
40 leased to close the circuit to the register on the
talking conductor, following which this latter reg
ister is actuated. In this case, it is necessary to
hold the cut-off relay operated to prevent thesub
scriber from reoperating the line relay and thus
disconnecting the register before it is operated.
These and other features of the invention will
5
individual to the line-?nder LF, shown in Fig. 1,.
and to the selector S. The line-?nder and selec
tor are of the well known Strowger type, but the
invention may be applied to systems using other
types of switches.
The subscriber’s set at W, known as the ring
subset, is equipped with an identifying space-dis
charge tube T, so arranged that the removal of
the receiver from the receiver hook disconnects
the tube from the associated line. This tube may
be of any desirable construction and may be
charged with any suitable substance such as neon.
be more clearly understood from a consideration The subscriber’s set at J, known as the tip subset,
of the following detailed description, which should is not equipped with a space-discharge tube.
be taken in conjunction with the accompanying Each station is also equipped with a dial for con
drawings, and also from‘ the appended claims.
trolling the operation of the switches used in
The drawings comprising Figs. 1 and 2, disclose extending a connection to the called station.
a portion of a step-by-step dial system in which
The line-?nder switch is equipped with two
the invention is embodied.
banks and two sets of brushes similar to the
Fig. 1 diagrammatically represents two sub switch disclosed in Patent 1,809,124, issued to
Vscribers’ stations J and W connected by a com Hovland on June 9, 1931, but the associated cir- 55'
2
2,008,281
cuit is somewhat different from that shown in I!!! connects the ring conductor of line I 00 to
the patent to Hovland. Upon the origination of conductor 523 and also closes a circuit for oper
a call at either of stations J or W of line I08, the ating group relay I63, from ground at the'back
line-?nder LP (or, if this line-?nder is busy, contacts of the cut-01f relay I {12, through the
some other line-finder to whose terminal bank upper inner front contact of relay I D I, resistance
the line ‘tilt; is multipled) is effective to associate IM, and through the winding of group relay I03
’
the proper set of brushes with the terminals to, to battery.
In operating, group relay I03 closes a circuit
which the line is connected. The calling line is
thereby extended to the trunk circuit which serves from ground through its lower front contacts, over
10 to connect the line-?nder with its associated conductor I05, through the upper back contacts 10
of relay E06, back contact of vertical magnet I01,
normally closed contacts of the “10th vertical
ance with this invention to identify the calling step” springs, winding of relay I I2, back contact
station on a two~party line and to operate the of rotary magnet I98, closed contact of the “10th
rotary step” springs, and through the lower back 15
15 message register which is individual to the call
selector S.
The trunk circuit T-—~i is arranged in accord
ing station. In order to determine the accuracy contact of relay I06 to battery. The closing of
of the ?rst or identi?cation test, two subsequent this circuit is effective to operate the interrupter
tests are applied to the calling subscriber’s line. relay I I2. Relay I I2 closes a circuit from ground
The ?rst or identi?cation test is applied after the through its front contact, the upper outer back
contact and lower winding of relay I I0, and
battery is connected to the tip and ring conduce through the winding of vertical magnet ID‘! to
tors of the calling line through the test relay 2% battery. The vertical magnet I0‘! is thereby
to detec the presence or absence of the space
operated to advance the shaft and brushes of the
discharge tube T and thereby identify the callé line-?nder LF up to the first level; but relay H0
25 ing subscriber’s station. Thus, if the call origi is slow to'operate and does not operate on the
nated at station J, the aforementioned battery pulses of current through its winding during the
will beirnpressed across the electrodes of the vertical movement of the switch. The vertical
space discharge tube T, associated with station off-normal springs VON are actuated when the
20 ?rst digit has been dialed, whereupon the test
W, thereby causing the said tube to ionize and
30" become suf?ciently conductive to provide an oper
shaft is advanced out of its normal position there
by connecting' ground to- conductor I I3. The 30
ating circuit for test relay 2136. If the call origi operation of magnet I01 also opens the circuit
nated at station Wjthe space-discharge tube is through the winding of relay H2, thereby caus
disconnected from the circuit, when the receiver ing the release of relay I I2. The release of relay
at the calling station W is removed from the re
3 I 2 opens the aforementioned circuit through the
35 ceiver hook, and consequently the test relay 200 lower winding of relay I Hi and winding of vertical 35
does not have an operating circuit.
magnet Illl', thereby causing the release of mag
rThe second test is made, after the calling sub net I07. The release of magnet I0‘! again closes
scrib-er disconnects following a completed call, to the circuit through the winding of relay II2.
determine whether there is a resistance leak of
40
excessive conductivity from the line conductors
of the calling line, to ground. This test is made
byconnecting the negative pole of the central
oii‘ice battery to the tip and ring conductors of
the calling line through the winding of relay i.
This voltage is not sufficient to ionize the. tube
T, but, if a leak of sufficient conductivity exists
between the line conductors and ground, relay
Zili will operate and prevent subsequent registra~
tion.
If the leak test is satisfactory, as indi
cated by the non-operation of relay iili, a third
’ test is initiated, to determine whether or not the
space-discharge tube T is in operative condition.
This test follows the second test and is made
Thus interrupter relay H2 and vertical stepping
magnet I01 alternately operate and release to 40
advance the shaft andbrushes of line-?nder LF
until the level of the calling line is reached.
Let it be assumed that line I 00 is connected to
terminals in the ?rst level of the upper bank and
that the aforementioned operation of group relay 45
M13 is effective to connect ground through the
upper outer back contact of cut-off relay I02, the
upper inner front contact of relay I0 I, resistance
set, and through the upper front contact of
relay’ I03, to the ?rst segment of commutator C. "
When the shaft and brushes have been advanced
to this level, a circuit is closed from the grounded
?rst segment of commutator C, through com
by reassociatingthe test relay 2% with the tip mutator brush I4, upper winding of relay I09,
and ring ‘conductors of the calling line. The test winding of relay II2, back contact of rotary
" relay
if operated under this condition, indi
magnet I08, closed contacts of the “10th rotary
cates that the space-discharge tube is functioning satisfactorily; but, if relay 280 fails to oper
ate, an unsatisfactory test results and subse
quent operation of the message register asso
ciated with the subscriber’s line is blocked. These
operations are best explained by a detailed de~
scription of the operation of the circuits shown in
the drawing.
_
step” springs to battery at the lower back con
tact of relay I96. Relay H2 is held operated in
this circuit even though the vertical magnet I07
has opened its back‘contact; but relay I09 is 60
marginal and does not operate at this time. Be
lay H2 maintains the operation of vertical mag
net I0'I in a circuit including the lower winding
Assume that a call is originated by the removal of relay MD as aforementioned. This circuit is
65
of the receiver from the receiver hook at either closed for a suf?cient length of time to partially 65
operate slow-temperate relay IIE. Relay H0’ is
of stations J or W, that brushes Iii‘), lit and Ill
are associated with lines terminating in the upper energized suf?ciently to operate its inner upper
group and that brushes Mil, H9 and Hill are front contact and thus close a circuit from ground
associated with lines terminating in the lower at upper contacts of VON springs, upper inner
group. Line relay lei operates in an obvious cir front contact of relay 'I I0, thence in parallel, one ''
cuit over the line we thereby connecting its lower path extending through the upper winding of
winding in parallel with the winding of the cut relay H0 to battery at the lower back contact
off relay in‘! and in parallel with tip party (J ) of relay I06, and the other extending through
register 522 to the sleeve terminal associated with resistance I2I and upper winding of relay III to
‘line iililin the bank of line~?nder LF; line relay battery. Relay H0 is completely operated in this
3
2,008,281
circuit; but relay III is marginal and does not
operate at this time. Relay I I0 opens the circuit
through the vertical magnet thereby causing its
release. The release of magnet I0‘I again closes
the circuit through the winding of relay I I2, over
conductor I05 to the ground at group relay I03.
and thereby prevents a 'false‘operation of relay
III.
.
i
'
~ The aforementioned operation of cut-off relay
I02 disconnects the conductors of line I00 from
the windings of line relay IEIi but relay IOI does 1-;
notrelease since its holding winding is energized
In case the calling line is connected to terminals in parallel with the winding of the cut-off relay
on the tenth level, the circuit through the wind I02. The operation of relay I02 also opens the
ing of relay I i2 is maintained through the lower circuit through the winding of group relay I03,
10 front contact of relay I I0, instead of through the and the release of relay I03 disconnects the 10:
“10th vertical step” springs. Relay I I0 also closes ground from start conductor I05. With brush‘I I5
a circuit for operating the rotary magnet I08; this in contact with the sleeve terminal of line I00 the
circuit may be traced from battery through the potential is such as to indicate that the line is
winding of magnet I08, the upper outer front busy and to prevent any other hunting switch or
15 contact of relay IIO, front contact of relay II2 connector from stopping on the terminals of this 15'
to ground at the lower inner back contact of line.
.
relay Ill. The operation of the rotary magnet
The complete operation of relay III extends
advances both sets of brushes into engagement the connection from line I00 through its upper
with the ?rst set of terminals in the previously front contacts to the winding of relay 206 and
selected level. Since the marginal relay I09 was thence through the windings of line relay 205 of 20.
not operated, brushes H5, H6 and III are effec selector S. The circuit for operating relay 205
tive on the call in question to the exclusiontof may be traced from battery through its upper
winding, upper outer back contact of relay 208,
brushes H8, H8 and IE0.
If the calling line is not connected to the first upper winding of polarized relay 206, upper outer
25 set of terminals in the [selected level, the sleeve back contact of relay 203, ring conductor 220,
terminal tests busy or idle, depending upon upper outer front'contact of relay I I I, upper mid
whether the line associated therewith is busy or dle back contact of relay I09, brush H6 and ring
idle; but in either case the interrupter relay H2 terminal of line ?nder LF, conductor I23, upper
is released by the operation of rotary magnet I 08. outer front contact of line relay IOI, ring con
30 The release of relay I I2, opens the circuit through ductor of line I00, through the calling subscriber’s 301
the winding of magnet I00. The release of mag instrument, back over the tip conductor of line
I 08 again closes the circuit for operating I00, through tip terminal and brush In of line
relay H2; and the reoperation of relay II2 closes ?nder LF, upper inner back contact of relay I09,
the circuit for reoperating magnet I08. Thus upper next to outer front contact of relay III,
35 the interrupter relay I I2 and the rotary stepping tip conductor 22I, lower outer back contact. of
magnet alternately operate and release to advance relay
lower winding of polarized relay 206,
upper inner back contact of relay 208, lower wind
ing of relayv 205, upper normally made contact of
“llth rotary step” springs, and through left wind
ing line are reached.
.
.7
40
When brush I i 5 makes contact with the sleeve ing of “dial tone” transformer 222 to ground. 40
terminal of the calling line, relay H2 is held op Relay III also releases the rotary magnet I08,
erated to prevent further advance of the brushes; closes an obvious circuit for operating relay I06
the circuit for holding relay II2 may be traced and connects a direct ground to sleeve conductor
from battery through the winding of relay I02, in I25 for holding the line relay IIlI and cut-off
parallel with the lower winding and front contact relay I02. This circuit may be traced from sleeve
of relay IOI, and in parallel with the Winding of conductor I25, upper next to inner front contact
register i222, sleeve terminal and brush II5, con of relay I l I to ground at the upper middle front
ductor I25, upper middle back contact of relay contact of relay I I0. Relay 205 operated as afore
I06, lower winding of relay III, front contact mentioned causes the operation of slow-to-re
of magnet I03, winding of relay II2, lower front lease relay 20'! in a circuit traced from ground 50
contact of relay I
back contact of magnet I01, at the lower outer back contact of relay 208, front
back contact of relay I00, and over conductor I05 contact of relay 205, and through winding of
to ground at contact of group relay I03. This cir relay 201 to battery. Relay 20'! connects a hold
cuit is also effective to operate the cut-off relay ing ground to sleeve conductor 209 and to hold
the brushes successively from one set of termi
nals to the next until the terminals of the call
I02; to operate relay III; and to hold relay IOI
operated. The tip party (J) register I22 is mar
ginal and does not operate at this time. The
current through the lower winding of relay III
electromagnetically aids the current flowing
60 through its upper winding su?iciently to close the
upper inner front contact of said relay and thus
close a circuit from battery through its upper
winding, hold conductor 2I0, lower outer back
contact of relay 2%, sleeve conductor 209, to
65 ground at upper middle front contact of relay
Ilél; the energization of the upper winding of
relay iII causes the complete operation of this
relay. If, during the rotary advance of the
switch, the sleeve brush IIE encoimters a busy
sleeve terminal, on which booster~battery is being
applied, for the purpose of operating the sub
scriber’s register, the current through the lower
winding of relay iII electromagnetically opposes
55
75
' conductor 2I0 so as to hold cut-off relay I02 and
relay III respectively and independently of the
ground at the upper middle front contact of relay
IIO. This circuit may be traced from ground at
upper front contact of relay 207, conductor 2I'I,
back contact of relay 2I8 to hold conductor 2I0 60
and through lower back contact of relay 204 to
sleeve conductor 209.
‘ Relay I06, operated as aforementioned, opens
the circuit through upper winding of relay I I0
and opens the circuit through the winding of re
lay I I2 thereby causing the release of said relays.
With relay I06 operated, the start conductor I05
is extended through the upper inner front con
tact of relay I06 to conductor I26 which leads to
thenext line-?nder in the'group.
If a call is originated over a line connected to
terminals in the lower bank associated with the
lower bank of the switch it is necessary that re
lay I80 be operated in order to associate the
the current flowing through its upper winding brushes II 8, H9 and I20 with the terminals of
70
4
2,008,281
lines terminating in this group. The initiating‘ 203 (a) transfers the tip and ring‘c'ondu'ctors 22!
of a call for a line, terminating in the lower bank, and 220 from the windings of relay 205 to the
‘causesthe operation of group'relay I03 as afore winding of identi?cation test re1ay'200, and (b)
mentioned. The line relays (not shown), for closes a circuit for. holding line relay 205 of selec
the lines associated with the lower bank of ter
tor S. This latter circuit is traced from ring con- ‘
minals are wired so that the aforementioned re
ductor232, upper winding of relay 206, upper
sistance m4 is not included in the circuit for op inner front contact of relay 203, through resist
erating group relay m3. Consequently, when the ance 223, upper outer back contact of relay 2|9,
commutator brush 44 makes contact with a com lower winding of relay 206 to tip conductor 233.
10' mutator segment, associated with the proper The release of relay 203 disconnects the‘ identi 10v
leve1,'the current through the upper winding of ?cation test relay from the tip and ring conduc
relay 509 is sufficient to operate this relay so as tors HI and 220 vand restores the continuity of
to render brushes l 68, l [9 and I20 effective to the
these conductors.
'
.
If the call originated at station J (tip party),
locks through its lower winding and front con the identi?cation test relay operates, during the
tact, over conductor M3, to ground at the upper time that its winding is connected to conductors
front contact of VON springs.
22l and 220 in a circuit traced from battery, lamp
When the subscriber at the calling station dials 224, resistance 225, winding of identi?cation test
the first digit of the number of the called station relay 200, back contact of relay 202, upper back '
the line relay 2535 of selector S is alternately re contacts of relay 204, front contacts'of relay 203, -20'
leased and reoperated each time the subscriber’s over conductors HI and 220, through'thefront
line loop is opened and closed at the dial. When contacts of relay I I l , line-?nder brushes‘ 5 H and
the line relay 28% of selector S releases, a circuit I I6 over the tip and ring conductors of line I00
is closed from battery, through the winding of and through the space-discharge tube T, at sta
the vertical stepping magnet 2! I, winding of re tion W, to ground through the ringer. The volt 251
lay 252, lower front contact of relay 201, back age applied across the tube, by’ the circuit just
contact of relay 205 and through the lower outer traced, is sui?cient to ionize said tube, thereby
back contact of relay 208 to ground. The mag rendering it sufficiently conductive so that the re
net 2 i l and, relay 2l2 both operate in this circuit. sulting current ?owing in the circuit operates re
Relay M2 is a slow-to-release relay and remains lay 200. If, however, the call originated at sta
operated until all of the impulses corresponding tion W (ring party) relay 200 does not operate.
exclusion of brushes H5, H0 and Ill. Relay I09
15
20
25
30
to each digit have been received.
Relay 2B’! is
for there is no identi?cation tube at station J and
also slow to release and holds during the receipt
the identi?cation tube T at station W is rendered
i this train of impulses. The operation of mag
ineffective, when the receiver at the latter station
35 net Zil steps the shaft and brushes of selector S
up to the first level of bank terminals. The reop
eration of relay 205 releases the magnet 2| l, and
each successive release and reoperation of relay
205 causes the operation and release of magnet
40 21 l.
The shaft and brushes of the selector are
raised in this manner, step-‘oy-step, to the level
through which the call may be extended toward
the called station.
-
As soon as the shaft of selector S is moved. olf
45 normal the vertical off-normal springs VON are
actuated and when relay 2 l2 operates as herein
before described, a circuit is closed, for operating
relay 263, from ‘cattery through the winding of
relay its, ‘upper contact of the VON springs,
front contact of relay 2|2 to ground at upper
front contact of relay 201. Relay 2 l2 also
, closes a circuit for operating relay 2 I4 from bat
is removed from the receiver hook. If relay ‘200
operates relay 226 also operates, in a circuit
traced from ground at the front contact of relay
200, lower innerback contact of relay 2|8'and
through the Winding of relay 226 to battery.
Relay 226 looks in a circuit through its upper
inner front contacts, upper middle back contact
of relay'2l8, to ground on conductor 2 ii.
The release. of relay 2l2 of selector S, after the
dialing of the ?rst digit, is also eifective to ‘close
a circuit for operating the rotary stepping mag 45
net 2|6; this circuit may be traced from bat—
tery through the winding of magnet 22!‘, lower
front contact of relay 213, normally closed con
tact of relay 2I2 to ground at upper front con
tact of relay 201. The rotary magnet 2|6 ro- =‘
tates the shaft of selector S one step so that the
brushes 228, 229 and 230 make contact with the
terminals of the ?rst trunk in the, previously
tact of relay M2 to ground at the upper front selected level. The operation of the rotary mag
55 contact of relay 207. Relay 2 I4 closes an obvious net causes the release of relay ‘M3. The release
operating circuit for relay 215. Relay 213 looks of ‘ relay 2|3 causes the release of the rotary
in a circuit from battery through its winding and magnet. The release of magnet 2H5 closes a
the upper contact of VON springs, through the circuit from battery through the winding of
back contact of rotary magnet'2l6, upper front relay 2 [3, upper contact of the VON springs, back
contact of relay 2 l3 and through the lower outer contact of magnet 2l5, conductor 23!, winding 60
back contact of relay 2518 to ground.
of relay 208, lower closed contact of “11th rotary
>When all of the impulses originated by the dial step”
springs to ground at relay 207. Conductor
ing of the ?rst digit of the called number have
been received, the release of relay 2 if! of selector 215i is also connected through the lower inner
back. contact of relay 208 and the sleeve brush
65 S opens the circuit for relay 2 [4/ Relay 214 re
leased closes a circuit for operating relay 203 to 220 to the sleeve terminal of the ?rst trunk in
initiate the identi?cation test. This circuit may the selected level. If this trunk is idle relay 208
be traced from ground at upper outer back con operates and relay 2| 3 does not operate; but if‘
tact of relay 25%, front contact of relay 2 l5, upper the trunk is busy the winding. of relay 208 is
inner back contact of relay 219 and through the short circuited by ground (not shown) at sleeve 70
winding of relay 2&3 to battery. Relay 2M also terminal 227 so that relay 2| 3 operates and relay
releases relay 2 l 5 but the latter is slow to release 208 does not operate. The reoperation of relay
and remains energized, after its operating circuit 2113 causes the reoperation of the rotary stepping:
is broken, for a sufficient length of time to com magnet 2l6. The alternate operation and re‘
plete the identification test. In operating, relay lease of relay M3 and magnet 2H5 advance the
tery through the winding of relay 2 l4, front con
2,008,281
10
15
20
25
30
5
brushes of selector S step by step from one set with respect to interrupter 234 that a time inter
of terminals to the next.
.
val of not less than two seconds elapses from
When an idle trunk is encountered relay 208 the time‘ ground is connected to the brush of
operates in series with relay 2E3; but relay 2| 3 interrupter 234 until ground is connected to the
is marginal and does not operate. Relay 208 brush of interrupter 235. The closed period for
disconnects the tip and ring conductors 233 and both interrupters is approximately 0.5 second.
232 from the windings of line relay 205 and ex This time delay is introduced to prevent a false
tends these conductors through brushes230 and indication of the charging operation if super
229 over the tip and ring conductors of the se visory relay 2% is momentarily operated due to
lected trunk to the windings of the line relay in trunk or line busy signal. Relay 2“! also pro
the second selector circuit (not shown). Relay vides a. second locking circuit for relay 2 l9. This
208 also establishes a temporary busy condition circuit is traced from lower. next to outer front
on the sleeve terminal of the selected trunk by contact of relay 2l8 through the winding of re
connecting the sleeve conductor 211 through the lay 2!!! to battery. With relay 2H3 operated,
lower inner front contact of relay ‘208 and brush sleeve conductor 2|‘! is disconnected from the
228 to the sleeve terminal 22?.‘ Relay 205 re sleeve conductor 209 and hold conductor 2H3, at
leases thereby causing the release of relay 231. the upper middle back contact of relay 2l8 and
Relay 201 is slow to release so that the ground is connected to relay 2“! at the upper outer
at its upper front contact is not disconnected front contact of relay 2E8; sleeve conductor 229
from sleeve conductor 2!‘! until sufficient time and hold conductor 2 H! are connected to ground,
has elapsed for the operation of the line relay through retardation coil 23'l, at the make spring
of the second selector (not shown) to have been of the upper middle inake-before-break springs
effective to cause a permanent ground to be of relay 2 I8. Relay 2M is energized from ground‘
connected from sleeve terminal 221, through on sleeve conductor 21? and in turn energizes
brush 228, and the lower inner front contact of slow-to-release relay 2E5 in an obvious circuit.‘
relay 283, to sleeve conductor 2V1.
Condenser 223 and retardation coil 231, asso
If all trunks in the selected level are busy the ciated with the sleeve conductors 2H and 209
selector, upon‘ reaching the 11th rotary step, of the selector S and trunk circuit T—l are fur
actuates “11th rotary step springs” thereby dis nished to provide a suitable path for the trans
connecting transformer 222, which supplies the mission of th'e‘usual‘number checking tone.
usual dial tone, from the lower winding of relay . When the calling subscriber replaces the re
205 and connecting thereto transformer 239, ceiver on the receiver'hook, the line relay of the
which furnishes a distinctive audible signal to connector (not shown) releases. The connector
10
15
20
25
30
indicate a “trunks busy” condition to the calling switch and associated second selector (not shown)
" subscriber.
are returned to normal in the usual manner.
.When the remaining digits of the called sta When the sleeve ground is disconnected from
tion’s number are dialed by the calling subscriber, the sleeve terminal 221 with which brush 228 is
the second selector (not shown) and connector in contact, relay 298 of selector S and relays 2M
(not shown) are operated in the usual manner and 206 of trunk T—l are released. The release‘
to extend the connection to the called subscrib of relay 208 closes ‘a circuit for operating the 40
release magnet 240 and selector S is returned to
er’s line.
‘
Assume that the called line is idle when con normal in the usual manner. In releasing, relay
nection is established therewith, that ringing po 2M closes a circuit to momentarily operate relay
tential is connected to’ the line, that the sub 202 for initiating the conductance test of the
45 scriber at the called station answers and that calling subscriber’s line. This circuit may be 45
the call is one for'which the calling subscriber traced from ground at the upper outer back
should be charged. When the receiver is re contact of relay 2| 4,‘ front contact of relay 215
moved from the receiver hook at the called sta upper inner front contact of relay 2 l9 and through
tion, the source of talking current at the con the winding of relay'202 to battery. This test
nector (not shown) for the calling subscriber’s is made to determine the presence or absence of a 50
line is reversed, with respect to the tip and ring resistance leak from either the tip or ring con
conductors of the line in the usual manner, so ductors of the calling subscriber’s line to ground.
as to operate the polarized supervisory relay 2% The necessity for this test resides in the condition,
wherein the ring party (W) initiates a call and
in the'trunk T‘—l.
,
.
‘
'The operation‘ of the supervisory relay 20$ wherein said leak is of sufficient conductance to
closes a circuit for operating relay 2“); this cir cause the operation of aforementioned identi?ca
cuit may be traced from battery through the tion test relay 2G0 and thereby identify the tip
winding of relay 2E9, front contact of relay 2%, partly erroneously. Belay 2&2 operates relay
lower back contact of relay ‘M9 to the brush of
When the brush of‘interrupter
234 is connected to ground relay 219 operates
and looks through the front contact of its make~
before~break springs to ground. Relay 21s dis
connects its initial operating ground at the brush
of interrupter 234i and closes a circuit for operat
60 interrupter 234.
203 in ‘an obvious circuit and connects the test
relay?!“ to tip and'ring conductors 22! and 228 60
respectively. This circuit may be traced from
battery through winding of relay 29 l , upper outer
front contact of relay 2G2, upper back contacts of
relay 204, front contacts of relay 2113 to con
ductors 22! and 22!! and thence over the tip and 65.
ing relay 2l3, from the brush of interrupter 235, ring conductors of the calling subscriber’s line
lower front contact of relay 2m, and through as aforementioned. The battery potential applied
upper inner back contact and winding of relay 218 to the ‘line ‘Hit, in this case, is not su?icient to
When the brush of interrupter 235 operate the space discharge tube T. If either the
is connected to ground relay 2E8 operates and tip or ring conductor of line it!) presents a re
locks in a circuit traced from ground at its lower sistance’leak to ground of excessive conductivity
outer front contact, upper outer back contact of relay 20! will operate in the circuit just traced.
relay 236 and through upper inner front contact However, if the line Elli) presents a resistance leak
of make-before-break springs and winding of to ground ‘of normal conductivity relay 2%“ will
- relay 2 l8 to battery. Interrupter 235 isso timed not operate.‘ If relay 28% operates it closes an
_ to battery.
6
2,008,281
obvious locking circuit for relay 202 thereby pre the operation of relay 236. This circuit may be
venting the subsequent release of thetrunk T—I traced from battery through winding of register
from subscriber’s ‘line I00. The trunk circuit I24, upper back contact of relay IOI, ring termi
T-I is so arranged that if its release is not
effected within a fixed time, starting from the
time the conductance test is initiated, the alarm
circuit (not shown) will function to attract the
attention of the maintenance force. The circuit
for initiating said alarm is traced from ground.
10 at the upper inner back contact of relay 2I4 and
through lower middle front contact of relay ?.I8
to the alarm circuit.
'
To proceed with this description we will assume
7 that the leak test is satisfactory.
Slow-to-re
lease relay 2 I5 releases thereby causing the release
of relay 262. Relay 203 however remains operated
in a circuit through its lower inner front contact
to ground at the lower outer front contact of
relay ZIB. The release of relay Z02 reconnects
the identi?cation ‘test relay 200 to the tip" and
nal and brush II6 of the line-?nder LF, upper
middle back contact of relay I09, upper outer
front contact of relay II I, ring conductor 220,‘
upper outer front contact of relay 203, upper outer
front contact of relay 204, upper middle back
contact of relay 226, lower back contact of relay
236, lower back contact of relay 226, and through 10
upper winding and upper inner back contact of
relay 236 to ground. The provision for operat
ing relay 236 in series with register I24 is made
for the purpose of testing the release of line relay
I0i. If said line relay fails to'release in series
with resistance 24I as aforementioned relay 236
will not operate, the trunk T—-I will be held'and
an alarm will be effected, as aforementioned. Re
lay 236 (a) locks in a_ circuit traced from bat
tery through its lower winding and upper next 20,.
ring conductors 22I and 226 in an aforementioned to inner front contact to ground at the lower
circuit, for applying the third test. This test outer front contact of relay 2I8; ((2) opens the
aforementioned locking circuit for slow-to-re
discharge tube T is in. operative condition and is lease relay 2I8; (c) connects a direct ground to
25 made immediately after the leak test at a time the sleeve conductor 209, to- guard against seiz
when the receivers at both the tip and ringsta ure by either another line-?nder or connector,
is made to determine whether or not the space
tions are on their respective receiver hooks as in a circuit traced from ground at upper next to
aforementioned.
outer front contact of relay 236, upper outer back
If the said identi?cation tube Tv is operative contact of relay 226 to sleeve conductor 209;
30‘ test relay 2% will operate as aforementioned and and (d) connects booster-battery to the ring con 80
. the trunk circuit T-—l will proceed to operate ductor 220 for the purpose of operating the ring
the proper meter associated with the calling sub party . (W) register I24. This circuit may be
scriber’s line; but if the test is not satisfactory traced from. booster-battery, through lamp 242,
test relay will remain non-operated and the trunk resistance 243, front contact of relay 236, upper
in this case will prevent registration and will back contact of relay 226, upper outer front con
cause the alarm circuit to function in an afore
tact of relay 204, upper outer front contact of
mentioned manner. The necessity for this test relay 203 to ring conductor 220 and thence
resides in the‘ condition wherein the tip party through the register I24 to battery over an afore
initiates a call and wherein the space discharge mentioned circuit.
40' tube T is not in an operative condition.
The
Having described. the operation of the circuit‘ 40
identi?caton test in this case should have caused to effect registration when the ring party (W)
the operaton of identi?cation test relay 200 there initiates a call, a description will now be made
by identifying the tip party; but with said tube of the operation of the'circuit to effect registra
in anon-operative condition said test relay re tion when the tip party (J) initiates a call. As
mains ncn~operated thereby indicating the ring aforementioned, relay 226 is operated and locked
party erroneously. Thus the accuracy of the when the identi?cation test relay 200 identi?es
identi?cation test is assured by the operation of the tip party (J). The operation of the circuit,
test relay 200. _
'
>
following the subscriber’s replacement of the re
‘As to the operation of the meters associated ceiver on the receiver'hook, is the same as de
with the two-party line I00; ?rst the operation scribed for the ring party (W) up to the point
of the ring party (W) register will be described where relay 204 operates. Since the tip party
followed by a description of the operation of the
(J) register I22 is associated with the sleeve cir
tip party (J) register. The operation of relay cuit of the line-?nder LF, by the line relay IOI,
200 causes the operation of relay 264 in a circuit it is not necessary to release relay IOI during
traced from groundat the front contact of relay the registration period. The line relay IOI is
20d, lower inner front contact of relay 2I8 and held operated in a circuit traced from ground
through winding of relay 204 to battery. Relay through winding of retardation coil 231, upper
204 looks through its lower inner front contact middle front contact of relay 2I8, lower front
to ground at the lower outer front contact of contact of relay 226, lower back contact of relay
60 relay 256.
The short circuit across resistance
24! at the lower outer back contact of relay 204
is opened by the operation of relay 204 and re
sistance Elli is included in series with sleeve con
ductor ‘206. This circuit may be traced from
sleeve conductor 209, upper outer back contact
of relay 226, resistance 24L upper middle front
contact of relay 2 I8 and through retardation coil
236, upper next to inner front contact of relay 60
226 to sleeve conductor 269 .and thence through
the Winding of relay I0! in an aforementioned
circuit.
Relay 204 operated closes a circuit for
operating relay 236 from ground at the lower
front contact of relay 2I8, lower middle front
contact of relay 204, upper next to outer front
contact of relay 226 and through the lower wind
23? to ground. The resistance'introduced into ing of relay 236 to battery. Relay 236 discon-‘
the aforementioned sleeve circuit causes the re nects ground from the sleeve conductor 209 and
lease of line relay IllI but does not affect the connects booster-battery thereto to operate the
cut-off relay I02. Relay IpElI released disconnects tip party (J) register I22. This circuit may be
conductor i23 from the ring conductor of line traced from booster-battery, through lamp 242,
I00, to prevent the initiation of another call until resistance 243, front contact of relay 236, upper
the register has operated, and connects the reg next to inner front contact of relay 226, to sleeve
ister :24 thereto, thereby closing a circuit for conductor 209 and thence through the winding
2,008,281
of register I22 in parallel branches extending
through contacts of relays I Ill and I 02. Relay
236 also opens the holding circuit for relay 2I8
thereby causing its release.
Relay 2I8 is slow to release and is designed so
that it will remain operated for a sufficient length
of time, after its holding circuit is opened, to
e?ect registration. This relay releases, following
the operation of relay 236 as aforementioned,
10 thereby releasing relays 2I9, 203, 204 and 236.
Relay 236 removes ground from the hold conduc
7
disconnecting said device from the line, means for
making a test of the line to determine the pres
ence or absence of said device, means dependent
upon said test for selecting one of said registers
for‘operation, and means for testing said line to
determine whether said device is in operative
condition.
ll. In a telephone system, a line having a plu
rality of stations thereon, message registers, one
for each of said stations, a space-discharge de 10
vice at one of said stations, means effective when
a call is made on said line for testing the line for
the presence of said space-discharge device,
tor 209; releases relay 226, if operated; discon
nects booster-battery from the sleeve conductor
209 (for tip party registration) ; disconnects boost means controlled as a result of said test for se
15 er-battery from the ring conductor 220 (for ring lecting one of said registers for operation, and 15
party registration) ; and disconnects ground from means for testing the line to determine whether
the sleeve conductor 269 (for ring party registra said space-discharge device is in Working condi
tion). The trunk circuit T-I is thus released tion.
and all apparatus is restored to normal.
The dis
20 connection of either booster-battery, or ground
from sleeve conductor 209 causes the release of
line relay IOI (if operated) and cut-off relay
I02 thereby restoring the subscriber’s line circuit
to normal. The disconnection of ground from
25 the hold conductor 2I0 releases relay III of the
line-?nder LF.
Relay III released closes a cir
cuit for operating the release magnet I28; this
circuit is traced from ground at the lower outer
back contact of relay I I I, upper outer front con
tact of relay I06 and through the Winding of
release magnet I28 to battery. The operation
of magnet I28 causes the shaft and brushes to
restore to normal. With the VON springs thus
restored to normal position ground is disconnect
35 ed from conductor II3, thereby releasing relay
I09. Relay III also opens the circuit through
the upper winding of relay I06 thereby causing
the release of relay I06 unless said relay is held
operated through its lower winding and upper
40 inner front contacts to ground on starting con
ductor I05; thus relay I06 can not release it
starting conductor I05 is grounded due to the
origination of another call until the calling line
has been found by some other line-?nder in the
45 group. The release of relay I06 disconnects
starting conductor I05 from conductor I26 and
from the lower winding of relay I06. The line
5. In a telephone system, a line having a plu
rality of stations thereon, message registers, one 20
for each of said stations, a gas-?lled tube con
nected to the line at one of said stations, means
controlled by the subscriber for disconnecting
said tube from the line, means responsive to the
initiation of a call on the line for testing said
line to‘ determine whether or not said tube has
been disconnected from the line, means con
trolled as a result of said test for selecting one of
said registers, and means for subsequently test
ing said line to determine whether the tube is in 30
operative condition.
6. In a telephone system, a party line, reg
isters, one for each party on said line, a space
discharge tube connected to the line at one of
said stations, means controlled by the party at 85
said station for disconnecting said tube from the
line, means effective when a call is made at any
one of said stations for testing the line to deter
mine whether or not said tube is connected to the
line, means controlled by said test means for se 40
lecting one of said registers for operation, and
means effective as a result of the replacement
of the calling subscriber’s receiver for again test—
ing said line to determine whether vsaid tube is
in working condition.
45
'7. In a telephone system, a subscriber’s line, a
line relay therefore, a message register for said
line, an operating circuit for said register in
?nder LF is now ready for use on another call.
cluding one of the talking conductors of the line,
What is claimed is:
50
1. The combination in a telephone system of a means for holding the line relay energized dur 50
line having a plurality of stations thereon, a reg ing conversation over said line, and means for
ister for each of said stations, an identi?cation releasing said line relay to close said operating
device at one of said stations, means effective circuit.
8. In a telephone system, a party line, a line
when a call is made on said line for testing the
relay therefor, registers, one for each of the 55
55 line for the presence of said device, means de
pendent on the result of said test for selecting parties on said line, an operating circuit for one
one of said registers for operation, and means for of said registers including one of the talking con
testing said line to determine whether said de ductors of said line, means for holding the line
vice is in operative condition.
60
2. The combination in a telephone system of a
line having a plurality of stations thereon, a reg
ister for each of said stations, an identi?cation
device at one of said stations, means responsive to
a call by any one of the stations on said line for
testing the line to determine the presence of
said device, means dependent on the result of
said test for selecting one of said registers for
operation, and means to test said line after the
relay energized during conversation, and means
dependent on the station making the call for
releasing the line relay to close said operating cir
cuit.
9. In a telephone system, a line having a plu
rality of stations thereon, a line relay for said
line, a message register for one of said stations, 65
an operating circuit for said register including
the control conductor of said line, a second reg
ister ,for another of said stations, an operating
calling party replaces his receiver to determine circuit for said second register including one of
the talking conductors of said line, means for
70 whether said device is in operative condition.
3. The combination in a telephone system of holding the line relay in operated condition dur
a line having a plurality of stations thereon, reg ing the conversation period, and means for caus
isters, one for each of said stations, an identi? ing the release of said relay to close the operat
cation device connected to the line at one of said ing circuit of said second register.
75
75 stations, means controlled by the subscriber for
HENRY I-IOVLAND.
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