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Full text of "BT-431220 Trunk Circuit - Two way for Conn. to Machine Switching "A" Board"

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Western Electric Co., Incorporated, 
Engineerir^ 35ept«, 

Nev; York* 


Two Way - Ayrar^ged For Oross-Corjnection - To miscellaneous 
At « Special “A“ Board - Full Hechanical avitchirxg System. 

(3 Pages) Page #1. 
Issue ir2 BT'-431220* 
April 8 , 1921, 

Answering Jack And Lamp 


1, This twO'Hvay trunk circuit is used to hanAle traffic between a special “A'* 
position and a Stromberg-Oarlson exchange* It is also used for conpletirxg calls o 
^,r/3v. trsanivsi tant^e^T positions to a 3 Car Ison exchanCQ* 

Zt On :in inootnizig call from Stromber^Carlson exchange the line lamp liglits 
at the special A board, Waen the plug of an ansv/erir.g cord is inserted in the asso- 
ciated answering jack, the line lamp is extinguished and the talking circuit is closed# 

S. .aen tne plvg of ?. jaaiing oora or a Eanoal tandem c<M 
multiple jack at tfce special, A board, the line lamp lights at the otrombei^ -H 

exchange . 

4. Standard supervision is given both operators by reversirg; the tip and g 
circuits between the two ends^ 



5 . On an incomir^ call from a S*romberg-Carlson exchange B/,® ^ 

placing be,ttery on the sleeve lead of the multiple jacks relay. When 

and lighting the line lamp at the A board under oontro o , ; , limited 

the pl^ of an answering cord Is inserted in the jack af ^ 0-1 rfla^ ' 

line 1^ the CO relay operates, in turn operatir^ the rel^. 

operated releases tlie B relay and operates the OI-l o^f-^es, in 

tL line lar^. It also closes - srp^^/^e^ersTsIhr^olarity 

tufcn operating the 3-1 rel^. The operc-tion Av,r>niie'h the windirxps of 

of the battery to the tip and rir,g of toard frfflo lighting, 

tho A relay te prevent the supervisory l^P at the coruiect- 

and opens the circuit through the audible ringing sieU^l ’"'“l releas-, 

ion is taken down at the Stromberg-Carlson exobango, tte ^ ^ 

iug the S-1 relay ivhich battery to the 

answering cord through the mnd^r^s ‘ ^ .Xp^ of the cord is removed 

at tte “A- board as a discoruiect oS rated relays and 

from the answering jack at the special A board, releasx.^ all oieiat 

rcstorir^ the circuit to normal. 


■ • cr.'vpr-ial '‘A’ board, the release 

6. In case discorxxotion originates at from the 

of the CO relay relsases the Cl relay, '^^®«°™®X^^?f„^^P^f/^hrsupervisory lamp 
rir.g and tip of the line respectively ana thereoy lightings the supervi cry 

at the otrcmberg-Carlson board as a discoriuect signal* 

(3 Ps^es) Page #2, 
Issue #2 - BT-431220. 
April 6, 1920* 

V* './lien the plug of a special A callir^ cord or a nianual tandem cord is in- 
serted in a luultiple jack at tls special A hoard, the calling cord supervisory lamp 
lights and the A relay operates, operating the 01 relay* The operation of tie 01 
relay closes the tip and ring fciirough the repeating coil, lighting the line laij) 
at tlie Stromherg-Carlson ezchar^e, and operates the CI-1 relay which connects the 
audit le ringing signal lead to the tip of the line sending a ririglng tone back to 
the calling subscriber* VJhen the call is answered at the Strauberg-Garlson e^:- 
cliar^e the line lamp is extinguished and the S -relay operates, operatirig the b-1 
relay v/hich opens the circuit through the audible ringing signal lead, and reverses 
the polarity of the battery flowing to the calling cord through the windings of tlB 
A relay, extinguisliing tiB cord supervisory lamp* VJhen tlie connection is talcen dov/n 
at tiie Btromberg-Carlson exclaange the supervisory lamp lights as a disconnect sig- 
nal, wlierer^on tlB plug Is removed from the multiple jack at the Special A board, . 
restoring the circuit to normal# If the plug of the cord is withdravvn first at 
the special “A" board the A relay releases, in turn releasing the Cl relay 'which 
causes the s’u^jervisory lamp at the Stromberg-Carlson board to light as a disconnect 










Spl.B relay 
per ]>*22637 ® 

opliS per 
]>-14961 3-1 



EInG » — HB H-RV • 


( SPages) Page #3, 
Is STUB #2 -* Bl!>-431220* 
April 8, 1920. 



After a soak of approx- 
isoately ,3 Amp, 

Test .OIS Amp. 

Ee-Adj. *016 Amp. 

After ^ soak of 
,3 Amp. 

Test .003 Aiip. 
Re-Ad j. .005 

Test ,023 Amp* 
Re-Ad j. .022 Amp. 

Test #007 Amp. 
Re-Ad j. *002 Amp. 

Test .0019 Amp. 
Re-Ad j. .002 Amp. 

Test .0006 A 2 np* 
Re-Ad j. .0006 

Test *029 Amp. 
Re-Ad j. .021 Amp. 

Test .014 Amp. 
Re-Ad J. .015 Anp. 

Test .0015 Amp. 
Re-Ad j. .0014 Amp. 

Test .040 Amp. 
Re-Ad^. .025 Amp. 

Test .045 Amp. 
Re-Ad j. .030 Amp. 

Test .0007 Amp. 
Re-Ad j. .0007 

Test .0047 Amp. 
Re-Ado* *005 

Test *0019 Amp. 
Re-Adj. .002 

CHK*I).— EGL,