GTE Omni Si Database Technical Practices Manual
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5210TL-130200-1001 START i-’IF THE PROBLEM IS NOT SOLVED, REINSERT THE ORIGINAL TRUNK CARD(S) AND REPLACE THE ASSOCIATED MPB85 CARD. (SEE NOTE). (END) NOTE: See paragraph l&5. Figure 5.9Trunk Operation Troubleshooting Flowchart 8187M-175
TL-130200-1001Tl -Type Trunk5.4 The Tl-Type Supervisory and Alarm Cards Maintenance(FB-20718-1A) have buffers which retain the status of the sense and control points (see Table 5.5). With the maintenance TTY, maintenance personnel can read or write into the digital trunk address in the same manner as with the analog trunks. Refer to Table 5.6 for trunk addresses. Be advised that analog trunk card locations are preempted from use when Tl is implemented. When referring to Table 5.5, note that the channel A and B signaling used with FX trunks does not provide for returning reverse battery from the CO. Therefore, the RB bit (bit 4 of the FX sense word) is an inactive bit and always appears as a 0 to the CPU. Bit 5 of the FX trunk work, the CF (Current Flow) bit, is a logic-gated sense point. The Tl-Type Supervisory Card gates the loop closure instruction forwarded to the far end with the detection of the IS (Incoming Seizure) sense bit to create the CF bit. BIT 7GD GS Table 5.5Sense and Control Words for Digital Trunks BIT 6BIT 5BIT 4BIT 3BIT 2 BIT 1BIT 0IS CFRBFX TRUNK SENSE WORD ISE&M TRUNK SENSE WORD LPFX TRUNK CONTROL WORD LPE&M TRUNK CONTROL WORD GD = Ground Detected GS = Ground Start IS =Incoming Sequence CF= Current Flow RB =Reverse Battery LP =Close Loop 81875210
5210TL-130200-1001 Channel Unit Removal 5.5 The Tl-tvoe interface cards do not detect removal of a loopstart chainel unit at the CO and use should be avoided. Table 5.6Trunk to Digital Span: Channel Correlation ANALOG TRUNK CARD LOCATION HARDWAREDIGITAL SPAN FILESLOTUNIV. POS ADDRESSCHANNEL IDENTIFICATIONIDENTIFICATION _. 19Cl051821X 051922051A 23 051 B24 17c20528 17X0529 18 052A190528 20 055B8 0568 1x 9C605692056A 3056B 4 8187M-l 77
--TL-130200-1001 Removal of a ground-start channel unit at the CC causes the GD (Ground-Detected) sense point, bit 7, in the FX trunk sense word Table (5.5) to become true, making the associated trunk busy to the system. Removal of an E & M or incoming loop dial channel unit at the far end causes an incoming seizure to the system. If the system data base is configured for the trunk circuit as a ringdown to the attendant, the removal of the far-end channel unit causes an incoming call to the attendant’s loop. If a channel unit at the CO channel bank is equipped with a busy key, operation of the busy key is equivalent to removing the channel unit from service. NOTE:The FX channel unit, when configured as a loopstart channel unit, is not detected as removed from service when the busy key is operated. Alarms5.6 The SYS LED on the Tl-Type Supervisory card (FB- 20718-1A) is activated when any one of the following occurs: 0 A local alarm * A remote alarm 0 A RPR ( remote power failure alarm) e When the digital trunks are in a loop test mode l When alarms above are off, but bit 2 (inhibit) is still being forwarded to the other end during the alarm restoral sequence. An alarm signal to the Tl-type Supervisory Card will be forwarded when the Frame, Detector card (FB-15278-A) determines that the frame sequence from the CO has been lost 81875210
TL-130200-1001 System alarms are associated with the system’s status as a slave. If the FB-20922-A Network Clock card should lose frequency synchronization with the SINX input for more that 2 seconds, a fault code 15 will be generated. When the FB-20922-A Card regains frequency synchronization on the SINX input, a response code is generated. When the RPF and SYS LEDs light (Tl-Type Supervisory card), a power failure has occurred in the CO terminating equipment. A power failure occurs when a normally operated device, such as a relay, restores and closes a Tl PF Tl (Power Failure) circuit grounding input lead in the Tl-Type Supervisory Card. When the power failure is detected, the RFP LED lights. If the power failure exists for longer than the local alarm (strapping option) threshold on the Tl-Type Supervisory Card, the local alarm is activated. If a common power source feeds the office terminating repeaters, only two or more power sources are used, wire one Tl PF and Tl PFG pair per power source. Testing5.7 The loop test determines if the Tl-Type interface can achieve frame synchronization.Before any loop test is initiated, all trunks must be in the maintenance busy state to avoid disconnection a customer from an established connection. To perform the loop test, set the AC0 (Alarm Cutoff) switch on the Tl-Type Supervisory card to the UP position, then set the LPT (loop) switch to the UP position. During the loop test, the incoming bipolar stream is terminated into a loo-ohm resistor. An all one (1) logic value is transmitted to the distant end. The outgoing unipolar transmit signal is looped back to the receiver side. The framing synchronization during the loop test is such that the incoming bipolar stream is offset one channel from the outgoing unipolar stream. If framing synchronization is achieved during the loop test, the SYS, ACO, and LOOP LEDs remain on. If framing synchronization is achieved in the system, but not with the far end, the span interface card may be defective. In most instances, if the loop test framing synchronization is achieved, it will also be achieved with the distant end barring any external wiring or repeater problems. If an alarm condition exists before a loop test, or if an alarm condition appears after the system is placed in loop test, the alarm state will persist for approximately 13.5 seconds. If the alarm condition persists longer than 13.5 + or - 3 seconds, a failure has occurred in one or more of the cards. 5210 8l87M-l 79
-!-L-l 30200-l 001 --To test the network clock synchronization, ensure that the Tl-type card group is frame-synchronized to the far end. Once this has been determined and the coaxial cables are properly connected between the Span Interface card and the Network Clock card, the SINX input can be cabled. If the SINX input cabled to a span interface card in an active Tl-type group cannot be selected, then that cable or span interface card is faulty. This testing can be done with the system off-line. The Tl-Type Supervisory Card must not be in the loop test mode. If more than one LED on the Network Clock card handle is on, the system is not frequency-synchronizing to a master clock. Tl Trunk Trouble5.8 Verify the the failure is not system related before starting any troubleshooting procedure on the digital trunk interface cards. Check the system fault log for codes 15 and 17. Trouble- shooting flowcharts for Tl are shown in Figures 6-25 through 6-28.The following failures have been categorized in four different modes on the digital trunk interface: 1. Supervision failure is the full or partial loss of supervisory signaling capability between the system digital interface and the distant-end equipment when the span is synchronized. 2. Transmission failure is the full or partial loss of voice (analog) signals over the digital span while the system is synchronized. 3. Frame synchronization failure (misframing) occurs when the system cannot identify the start of a frame in the incoming span. Misframing results in loss of communication from the far end. In misframing errors, the clocks are assumed to be running synchronously, but the digital trunk interface cards cannot decode the incoming span data properly and locate the 245channel frames. 4. A clock synchronization (frequency synchronization) problem, or loss-of-slaving condition, results when the system clock is running at a frequency other than that of the bit frequency on the incoming Tl-type span. The system can maintain frame synchronization, but because of differences in clock frequencies, it will occasionally skip over a frame and never decode that frame of information. The system is slipping frames. M-l 80 81875210
TL-130200-1001 STARTciSYSTEM HAS LOST PARTIAL OR FULL SUPERVISION IN THE DIGITAL TRUNK INTERFACE. IARE ANY FAULT CODES PRINTED ONREFER TO SYSTEM FAULT TABLES THE MAINTENANCE INO clA Figure 5.10Tl-Type Trunk Loss of Supervision Troubleshooting Flowchart (Sheet 1 of 7)5210 8h37
TL-130200-1001IS THESYSTEMbCOMMON TO THE SYNCHRONIZED? YESYESNO ;,PROBLEM STILL YES 1NO (--Z---l 1NO REMOVE AND REPLACE THE FOLLOWING DIGITAL TRUNK CARDS ONE AT A TIME. IF THE TROUBLE STILL EXISTS AFTER EACH REPLACEMENT, REINSTALL EACH ORIGINAL CARD. FB-17192-A TlB2FB-17277-A OR 15277-1 SILFB-15280-A LCM. Figure 5.10Tl-Type Trunk Loss of Supervision Troubleshooting Flowchart (Sheet 2 of 7) M-l 82 81875210
TL-130200-1001 PROBLEM STILLYES Figure 5.10Tl-Type Trunk Loss of Supervision Troubleshooting Flowchart (Sheet 3 of 7)5210 8A37M-183
TL-130200-1001D 70 B---CORRECT? YESTHE FB-20718-l NO IS THE PROBLEM RESOLVED? IS THE PROBLEMNO ‘IREPLACE f MB CARD. Figure 5.10Tl-Type Trunk Loss of Supervision Troubleshooting Flowchart (Sheet 4 of 7) 5210