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REF ID:A414~73 · 

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E. GRETENER 1,967,404 

SIGNALING APPARATUS 

Filed April 21, 1932 

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Patented July 24, 1934 1,967,404 

UNITED ST A TES PA TENT OFFICE 

1,967,404 

SIGNALING APPARATUS 

Edgar Gretener, Berlin, Germany, assignor to 

Siemens & Halske Aktiengesellschaft, Wernerwerk Siemensstadt, near Berlin, Germany 

Application April 21, 1932, Serial No. 606,735 

In Germany April 22, 1931 

12 Claims. (Cl. 179-84) 

This invention relates to the use of neon lamps 

operating as signal indicators or receiving relays 

for signal transmission in communication systems 

and preferably in telephone systems. 

5 According to one featw·e of the invention, the neon lamps are disposed in circuits coupled inductively to the lines. The lamp circuits are normally energized by a potential which is kept 

between the striking and the extinguishing volt10 age of the lamps. Signaling current applied to a line is superimposed on the circuit of the asso- ciated lamp, causing the lamp to strike. The 

lamp then remains lighted by the potential nor- mally applied to its circuit until the current is 

15 interrupted upon the call being answered. A very 

simple and inexpensive line signaling arrangement 

is thus provided. 

An additional feature of the invention relates 

to a method of supplying the neon lamps with 

20 an extra impedance so as to reduce their sensitive- ness to voltage peaks occurring during a con- versation. By means of this ararngement, the mean speech level also may be dropped according to the voltage of the neon lamps. 

25 The features of the invention are more fully 

explained in conjunction with the accompanying 

drawing, comprising Figs. 1 and 2. Fig. 1 shows 

the embodiment of the invention in a system em- ploying double ended cord circuits. Fi,g. 2 shows 

30 the embodiment of the invention in a system em- ploying single ended cord circuits. 

Referring now to Fig. 1, three lines Ll, L2, L3 

have been shown. A series of additional lines 

may be connected up in a similar manner. The 

35 lines are associated with corresponding neon lamps Gl, G2, G3, their circuits having a com- mon portion formed by the current source of 

supply El, from which the pre-applied potential 

is derived, and the relay R. Parallel with the 

40 current source of supply and relay R is connected 

the condenser Kl which serves the purpose of 

preventing a plurality of neon lamps from lighting simultaneously in consequence of the common coupling unit R. A connection between two lines, 

45 for example the lines Ll and L3, is made in the 

following manner: The neon lamp Gl lights up when the subscriber associated with line Ll initiates a call 

by ringing over the line. The exchange operator 

60· inserts the plug designated a', b', c' of the con- necting cord S into the corresponding jack of 

the line Ll and throws the change-over key U into 

the position in which enquiries are made, i. e. to 

the right.. Inserting the plug as mentioned causes 65· the primary winding of the repeater Tl to be disconnected from the line Ll, and the contact spring c is thrown from d over to e. This extinguishes 

the neon lamp Gl, and the following circuit for 

the neon lamp G4, provided to indicate the clearing signal, is prepared: positive pole of battery 60 

El, primary winding of the repeater T4, G4, e, c, 

negative pole of battery El. The contacts l, m and n are closed when the switch key U is set in 

enquiry position. Consequently the transmitter 

circuit for the operator's speaking set is closed 65 over E3, M, l, primary winding T5. The secondary 

circuit of the repeater T5 is connected to the line 

Ll over a circuit extending from secondary winding T5, receiver H, m, a', a, Ll, b, b', n secondary 

winding T5. The Ll line subscriber's request for a 70 

connection with the line L3 is duly noted and the 

plug a", b", c' ', of the connecting cord S is inserted into the jack which corresponds to the 

required line L3. The repeater T3 and the neon lamp G3 are then disconnected from the line L3, 75 and a second circuit for the clearing signal lamp 

G4 is prepared over the jack spring c and con- tact e. Ringing current is then transmitted to the 

subscriber connected to line L3 by the switch 

key U being turned over to the left. Contacts 80 

g, hare opened and contacts/, i and k are closed. 

The pole alternator P, which acts as a ringing cur- rent source of supply, is caused to operate over: battery E2, k, interrupter contact and magnet 

winding of said pole alternator. Positive and 86 negative impulses are alternately transmitted 

through the primary winding of the repeater T6 over contacts o and p with the result that cor- responding impulses pass to the line L3 over con- tacts t and i and the plug leads a." and b" and 90 cause the subscriber's ringer to operate. The 

condenser K3 may serve to smooth the ringing 

impulses. 

The switch key U is now restored to speaking 

position, that is to say, it is thrown into its cen- 95 tral position, and the connection between the two 

subscribers is then completed. The condenser 

K2 which is connected in parallel with the neon lamp G4 prevents said neon lamp from lighting 

up during the conversation due to voltage peaks. 

When at the end of the call one of the subscribers gives the clearing signal, the neon lamp G4 

is lighted due to the fact that the condenser K2 

is not operative with low frequency ringing current. Withdrawing the plugs a', b', c' and a", b", 

c" from the jacks causes the circuit over the neon lamp G4 to be cut off at contacts e. Fig. 2 shows a somewhat different arrangement in which each subscriber's line is permanently connected to a cord such as a', b', c'. 

100 

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REF ID:A4148A13 .... 2 1,967,404 

The switching units corresponding to Fig. 1 are provided with the same reference characters. The neon lamp GI is lighted when the subscriber asso- ciated with line Ll puts through a call. A momen- 5 tary depression of the key SI causes this lamp to 

be extinguished and the connection with the re- quired line, for example the line L2, is set up. 

The plug leads a', b', c' are connected to the cor- responding jack springs a, b, c of line L2, thus ~o causing the repeater T2 to be disconnected from 

line L2. The neon lamp Gl remains connected 

to line Ll, over the repeater Tl since it is adapted 

to operate as a clearing signal as well. The con- denser K3, which is connected to the plug lead c' 

15 and to the jack spring c of line L2, and conse- quently also to the left hand side of the neon lamp 

GI over the jack springs a of the lines L2 and Ll, so that it, therefore, is connected in parallel with 

said lamp, prevents the neon lamp from lighting ~o up in consequency of voltage peaks occurring 

during the conversation. The neon lamp GI is re- lighted at the end of the call and therefore acts as a clearing signal. 

What is claimed is: 

25 1. In a telephone system, a line terminating in a primary winding of a repeating coil, a neon 

tube, a local circuit for said tube including the 

secondary winding of the repeating coil and a source of current whose potential is between the 

;,J striking and extinguishing voltages cif the tube, 

and manually controlled means for opening said 

local circuit. 

2. In a telephone system, a line, a repeating coil 

having its primary winding bridged across the line, 

;;.; a neon tube associated with the line as a calling 

signal, a local circuit for said tube including the 

secondary winding of the repeating coil and a source of current whose potential is between the 

striking voltage and releasing voltage of the tube, 

•-i.l means for extending a connection to the line, and 

contacts controlled by said last means for disconnecting the repeating coil from the line and for 

opening said local circuit. 

3. In a telephone system, a plurality of lines 

-±5 each terminating in the primary winding of a repeating coil, a neon tube associated with each 

of said lines as a calling signal, a common circuit 

including a source of current, a relay and a con- denser, and a local circuit for each of said tubes, 

..;.i each circuit including the secondary winding of 

the associated repeating coil and said common circuit. 

4. In a telephone system, a line, a neon tube 

associated with the line at the exchange, circuit 

connections for causing said tube to strike respousive to a call signal on the line and to remain 

lighted, and manuany controlled means for momentarily opening said circuit connections to ex- tinguish the tube whereby the same is prepared to c~ strike in response to a disconnect signal. 

70 

75 

5. In a telephone system, a line, a neon tube as- sociated with the line, circuit connections for 

causing the tube to light responsive to a call signal on the line, means for answering the can and 

for extending the same to the called line, and means responsive to the extension of the call 

for connecting a condenser in parallel with said 

tube. · 80 

6. A telephone system as claimed in claim 4 in 

which current of a potential insufficient to cause the tube to strike but sufficient to prevent it from 

extinguishing is normally applied to the tube independent of the line. 86 

7. In a telephone system, a plurality of lines 

each terminating in the primary winding of a repeating coil, a common source of current, a neon tube associated with each line, a local circuit for each tube including the secondary wind- 9() 

ing the associated repeating coil and said com- mon current source, means responsive to a call on a line for lighting the associated tube, a cord 

circuit adapted to connect with the lines to answer calls thereon, a neon tube adapted to 95 

operate as a disconnect signal for any of said 

lines, and means responsive to the connection 

of the cord circuit to a calling line for opening 

the local circuit of the tube associated with the 

line, for completing a local circuit including said 100 common current source for said other neon tube, 

and for inductively connecting said last men- tioned local circuit with the line. 

S. A telephone system as claimed in claim 7 

in which the neon tube used for the disconnect 10.7 

signal is shunted by a condenser to render it 

less sensitive to current peaks set up during con- versations. 

9. In a telephone system, subscribers' lines, means including a cord circuit at the exchange UC 

for connecting two of said lines for conversation, a neon lamp associated with said cord circuit as a supervisory signal, and circuit connections 

for said lamp such that a ring off signal received at said cord circuit will cause the lamp to na 

operate. 

10. In a telephone system as set forth in claim 

9, means for extinguishing the lamp when the 

connection ls pulled down. 

11. In a telephone system, a plurality of sub- 120 

scribers' lines, means at the exchange for con- necting two of said lines in a talking circuit, a neon lamp at the exchange functioning as a disconnect signal, a source of current applied to 

said lamp to maintain the same operated after 125 

its operation has been initiated, and circuit con- nections between the talking circuit and said 

lamp such that ringing current transmitted over one of the connected lines will initiate the operation of said lamp. 130 

12. In a telephone system, subscribers' lines, means for answering a call on one of said lines 

and for connecting the same with another of 

said lines, a neon lamp, and circuit connections 

for said lamp such that the same operates as a 135 can signal to call the operator and as a supervisory signal after the connection is completed. 

GRETENER, EDGAR. 

l9'G 

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