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Full text of "BT-431304 Ringing Circuit - For Secondary Testing Cord Circuit - Local Test Desk"

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Western Electric Co., Incorp< 
Engineering Dept*, 

New York. 


3a a 


{ ,^ i'agesj i'ago 7/ .1 * 

Issue 2 - BT- 43 1304. 
April 21, 1920. 


For Secondary Testing Cord Circuit 
Driven System. 


METHOD OF OPERATION 
RINGING CIRCUIT 

- local Test Desk - Full Mechanical Power 


GENERAL DESCRIPTION 

1. These circuits are used in a local test desk at a mechanical office 
m connection with primary and secondary testing cords to provide means for * 
semi- selective ringing of the stations on a two or four party line! 

DETAILED DESCRIPTION 

1 

OPERATION 


F IGURE #l _ ._TY/0 OR _FQUR PARTY SEMI- SELECTIVE RINGTTJft 


2. When the subscriber’s line under test is selected by means of a 
sender, the PMG or SMG relay in the testing cord circuit operates furnishing 
ground to the lead C. Bum the R or M key is operated, the R rel^y o^rltes 

f h° m l attery throu g h its winding, break contacts of the T-l 
slays, break contact of the RR relay, make contact of the R or M kev 
to ground on lead C. ffie R relay operated, finishes battery to the ?200 oto 
winding of the PU relay which operates under control of the pick-up inter- 
rupter and locks through its make contact, connecting "2 RING" machine ringing 
cui rent oO the ring or tip of the line according to the key operated. The PU § 
us ® d I* th ® circ uit to apply ringing current at the start of the 
2 RING code thereby preventing a false code. When the receiver is removed 
from the switclihook at the called station, the T-2 relay operates removing the 
short circuit from the winding of the RR relay which operates in series with 
the R reiay. Tne RR relay operated functions as follows:- (a) Disconnects 
lunging current from the tip and ring leads T-l and R-l. (b) Lights the TR 
lamp, (c) Opens a contact to prevent its being short circuited upon the re- 
lease of the T-2 relay, (d) Connects ground to the tip side of the subscriber’s 
line and the supervisory relay on the ringside of the secondary testing cord 
circuit to the ring of the subscriber’s line for supervisory purposes. When 
the test man restores the ringing key, the R and RR relays release, restoring 
the circuit to noraal. e 


3. When the 17 or J party key is operated, the circuit functions as 
above described with the exception that the "1 RING" test machine ringing cur- 
rent is applied by the key to the ring or tip of the line through the T-l re- 
lay directly and independently of the PU relay. 

FIGURE #2. TWO PARTY SELECTIVE RINGING 

4* The operation of the AICT key to call either of the two stations 
performs the same functions as above described for the operation of the "W" 
or "J" keys. The only exception is that the R relay of Figure #1 is here 
replaced by a #18-G resistance. 



OPERATE 


CIRCUIT REQUIREMENTS 
mi- OPERATE 


114- AK 

With ringing ma- 

Y/ith ringing ma- 

(T) ( T-l) 

chine at 

approx- 

chine at 

appr ox- 

and (T-2) 

imately 1200 R,P.H. 

imately 

1200 R.P.M. 


Test 

.033 amp. 

Test 

•029 amp. 


Read j • 

.032 amp. 

Readj. 

.030 amp. 


With ringing ma- 

With ringing ma- 


chine at 

appr ox- 

chine at 

approx- 


iraately 

1000 R.Pja, 

imately 

1000 R.P.M. 


Test 

•037 amp. 

Test 

.033 amp. 


Roadj. 

•036 amp. 

Read j • 

•034 amp. 

E75 

Test 

.035 amp. 



, 

Road j . 

.011 amp. 



E212 

Test 

.045 amp. 

Test 

•028 amp. 

(HR) 

Readj • 

.040 amp. 

Readj. 

.030 amp. 

• 

Sp 1. E 

Test 

.011 amp. 



per 

Readj. 

.010 amp. 



D- 12829 





Inner V/dg. 



\) I , : f: i< ; 




(2 Pages) Page #2. 
Issue 2 - BT- 43 1304 
April 21, 1920. 



Test *0026 amp. 
Read j . .0026 amp. 


Test '.0023 amp. 
Readj* .0025 amp. < 

/, i ' * "• ■ 





iOv ; <’A 

4 v ^ USDO $ 


‘ENG.— WES- JO. 


CHK # D.— CHW. 


•' APPROVED - C.L. SLUYTER, G.M.L. 


fir fin