. The Bell System technical journal . The 40 verticals of the latter are con-nected directly to the 40 test set feature circuits designated 0-39. Two additional 10 X 20 crossbar switches perform the function ofconnecting any of the five power or five multiple terminations to anyof the forty test set features. These terminations are comprised of 5loops and one each of ground, negative 24 volts, negative 48 volts, 90-volt 20-cycle ringing current and positive 130 volts. Thus it can be seen that, through proper operation of the primary,secondary, tertiary and terminating crossbar switch cross poi
. The Bell System technical journal . The 40 verticals of the latter are con-nected directly to the 40 test set feature circuits designated 0-39. Two additional 10 X 20 crossbar switches perform the function ofconnecting any of the five power or five multiple terminations to anyof the forty test set features. These terminations are comprised of 5loops and one each of ground, negative 24 volts, negative 48 volts, 90-volt 20-cycle ringing current and positive 130 volts. Thus it can be seen that, through proper operation of the primary,secondary, tertiary and terminating crossbar switch cross points, apath can be established from any circuit terminal to any test set featureand supplied with any of the available power or loop terminations. It is 7 CROSSBARSWITCHES RELAY SWITCHING TYPE CIRCUIT UNDER TEST MAX. 99LEADS AUTOMATICSWITCHING OF CIRCUIT TERMINALS TO DESIRED TEST FEATURES QUICK CONNECT CONTACT FIXTURES TELETYPE TRANSMITTER MODIFIED FOR 5-WIRE OPERATION 40 LEADS CONNECT «. DISCONNECT SIGNALS TRANSMITTED CODES 5 LEADS. TESTFEATURES CIRCUITS APPLY DIFFERENT TESTS AND CHECKING CONDITIONS 40LEADS TEST FEATURE SIGNALS TAPEDECODINGCIRCUITS 10 KEYS OPTIONALFEATURESCIRCUITS PERMITS VARIATION OF TEST LISTED ON STANDARD TAPES TEST SIGNALS AND CHECK RESPONSE 2 CROSSBARSWITCHES CONTROLCIRCUITS A SPECIAL CODE ATEND OF EACH TESTSTEP PERMITS THESECIRCUITS TO TRANS-FER CONTROL OF THETRANSMITTER TO THECHAIN LEAD RESET KEY INDEXES TAPE i^TO STARTINGPOSITION i TERMINATIONSWITCHINGOF POWER8. SIGNALSt130VDC GROUND90V PO^ RING 5 LOOPS-48 V DC -24 V DC TO TESTFEATURES CIRCUITS TERMINATION SWITCHING SIGNALS TROUBLE INDICATING CIRCUITS 1. LAMPS INDICATEPROGRESS OF TESTAND ANY FAILURES 2. INDICATES FAILINGCIRCUITS 3. SHOWS POSITION OFRELAYS IN TESTEDCIRCUITS (-—CHAIN LEAD CHECKS POSITION OF ALL TESTFEATURE RELAYS WITH WATCH-ING RELAYS. IF CHAIN ISCLOSED, TAPE IS INDEXED TONEXT TEST CODE CHAIN IS OPEN, CONTROLCIRCUIT WILL SWITCH TOTROUBLE INDICATING CIRCUITS START KEY STARTS
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
