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Full text of "BT-431461 Telephone Circuit - Sender Monitoring Position - Trouble Desk"

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(3 Pages) Page #1 
Isme 6 - BT-431461. 
Spptember 29, 1920. 


Sender Monitor's Position - Arranged To Trip Machine Ringing - And To Give Su- 
pervision lo Zero Operator - VJith incoming Call Feature - Trouble Desk - Full 
Mechanical Power Driven System. 


1. This circuit is used to connect to the trunk, tie line and cord 
circuits which terminate' in a sender monitor's position. 

2. When the plug of a sender monitor's cord is inserted in a jack of 

a line germinating at the position, the telephone circuit is connected across 
the cord of the trunk for talking. During the time the operator is busy, 
the incoming call circuit is disconnected from the trunk circuit and it is 
connected to a. tone circuit. If the distant operator comes in on the call 
circuit a tone will be received as a notification that the called' operator 
is- busy. At the same time a lamp is lighted at the called position as an 
indication that an operator is awaiting on the call circuit. When the 
calling operator releases the call circuit key, the lamp is extinguished 
and the tone is removed. When answering calis having machine ringing such 
as incoming calls on plugging up lines, the ringing is tripped before the 
operator is connected to the line. 

3. This circuit is provided with a secondary cut-out key which connects 
the receiver across the tip and ring of the circuit and cuts out the second- 
ary of the induction coil and also ringing key for ringing on outgoing calls. 

4. The circuit is arranged to provide supervision on calls to or from ' 
the zero operator s position. 

5. Should 'cue operator answer a call having manual ringing the operator* s 
set is not connected across the circuit until the ringing ceases. 



6. The insertion of the plug of a sender monitor* s cord circuit in the 
jack of a plugging-up line operates The CU relay and the T relay in series 
after certain functions have been performed in the cord circuit. The T 
relay operated, connects the telephone set to the cord and disconnects the 
iP relay from the tip and ring of the cord* The CVJ relaj/ operated, removes 
the tip and ring of the incoming call circuit from the telephone set and 
connects the ring to a tone circuit. 

Western Electric Co., Incorporated, 
Engineering Dept. , 

New Jerk 

(3 Pages) Page $2. 
Issue 6 - BT-431461. 
September 29, 1920. 

At the same time, battery and ground are connected to the ying and tip respectively 
of the incoming call circuit through the windings of the CT7-1 relay. Under this 
condition, if a key associated with the distant end of the incoming call circuit is 
depressed the CU-1 relay operates through the calling operator's telephone circuit 
lighting a pilot lamp as an indication that an operator is waiting on the call 
circuit. Hie release of the outgoing call circuit key at the distant operator's 
position releases the CY/-1 relay, extinguishing the lamp. If a call is ansv/ered 
while manual ringing is connected to the line the TP relay operates on ringing- 
current over the T and R leads. The TP relay operated, opens the S lead thereby 
preventing the CJ7 and the T relays from operating, and the telephone set is left 
disconnected from the tip and ring of the cord, when the ringing current is re- 
moved the TP relay releases, allowing the T relay and the CYJ relay to operate 
in series* 

7. Y/hen the plug of the sender monitor's cord circuit is withdrawn from the 
jack of the line, after certain functions have been performed in the cord circuit 
the T and the CYT relays are released disconnecting the telephone set from the cord, 
connecting the TP relay across the cord and disconnecting the ring of the incoming 
call circuit from the tone circuit. 

8. Y/hen the operator flashes on a connection by operating the "Flash" key, 
the distant operator's challenge will be transmitted from the tip and ring of the 
line to the telephone set over leads TF and RF* 

9. Y/hen the position is idle the twin plug of the head set is withdrawn 
from the receiver jack, disconnecting transmitter battery. 

( 3 Pages) Page 3 
Issue 6 - BT-431461 
September 29, 1920. 




Test .0016 amp. 
Readj. .0015 amp. 



Test .0005 amp. 
Readj. .0005 amp. 


After a soak of 

After a soak of 





.009 amp. 

.009 amp. 

in series Test .0043 amp. 

Test .00312 amp. 


Readj. *0028 amp. 

Readj. .0013 amp. 


Test .023 amp. 

Test .013 amp. 


Readj. .018 amp. 

R ead j • .014 amp . 


Test .027 amp. 

Test .014 amp. 


Readj. .025 amp. 

Readj. .015 amp. 





G.I-’i. L.