308 



THE BELL SYSTEM TECHNICAL JOURNAL, MARCH 1953 



MARKER SEIZURE 

 TRANSFER OF CALLED 

 NUMBER TO MARKER 

 SEIZE TRK LK FRAME 

 TEST 1ST CHOICE INTRA- 

 OFFICE TRUNKS 

 SEIZE TRK LK FRAME 

 TEST 2ND CHOICE INTRA- 

 OFFICE TRUNKS 



ii 



TIME 



TRUNKS BUSY 



1 



TRUNKS BUSY 



SEIZE NUMBER GROUP --X- 



TEST PBX LINES 



SEIZE TERM. LLF 

 TEST LINE 

 MATCH CHANNEL 



RELEASE TERM. LLF --- 



SEIZE ORIGIN'T'G LLF_ 

 MATCH CHANNEL 



RELEASE TRK LK FR 

 RELEASE ORIGIN'T'G LLF' 



SEIZE TRK LK FRAME 

 TEST 2ND CHOICE INTRA- 

 OFFICE TRUNKS 



^MISMATCH 



i-N LINE 



BUSY - 



SEIZE NUMBER GROUP 



TEST PBX LINES 



SEIZE TERM. LLF 

 TEST LINE 

 MATCH CHANNEL 



RELEASE TERM. LLF- 



SEIZE TRK LK FRAME_ 

 TEST TONE TRUNKS 



SEIZE ORIGIN'T'G LLF 

 MATCH CHANNEL 



RELEASE TRK LK FR 

 RELEASE ORIGIN'T'G LLF 



SEIZE TRK LK FRAME 

 TEST TONE TRUNKS ' 



SEIZE ORIGIN'T'G LLF 

 MATCH CHANNEL 



RELEASE TRK LK FR 

 RELEASE ORIGIN-T'G LLF~ 



SEIZE TRK LK FRAME 

 TEST TONE TRUNKS 



SEIZE ORIGIN'T'G LLF 

 MATCH CHANNEL 



RELEASE REGISTER 

 RELEASE TRK LK FR,LLF 

 MARKER RELEASE 



MIS- 

 ^ MATCH 



TRUNKS 

 BUSY 



^ MIS-- 

 MATCH 



Jk 



X ~ - 



PBX LINE 



LINE BUSY 



TRUNKS 

 BUSY 



>-LINE BUSY 



MIS- 

 MATCH 



-X— -X — ^x-- 



SET REGISTER FOR TONE 

 RELEASE TRK LK FR, LLF 

 MARKER RELEASE 



■MISMATCH 



I MISMATCH 



i 



MIS- 

 MATCH 



X---X — ^x- — 





MISMATCH 



LINE 

 BUSY 



MIS- 

 MATCH 



I MIS- 

 MATCH 



-R— 



:^-' 



MISMATCH 



— f 



MISMATCH 



i 



"f MIS- 

 MATCH 



-X---X — ^x 



Fig. 5 — Possible variations in handling an intraoffice call. 



