AT&T DS1/DMi/ISDN-PRI manual 2SAMPLE Installation and Maintenance Problems, Transmission Facility

B-2SAMPLE INSTALLATION AND MAINTENANCE PROBLEMS

●Versatility

●Complexity of installation

●Administration

●Operation

●Type of alarms

When a DS1/DMI facility fails to operate (because of a line failure), the first choice in diagnosing the problem is to check the translations. Mistakes in translating procedure 260 are identified by comparing the translations and equipment options from one DS1/DMI and all intermediate equipment to the other DS1.

NOTE: Procedure 260 has one field entry that affects the fault codes displayed in procedure 620. External loop-around is used only during fault isolation in procedure 620 test 2. Normal operation requires this field to be off or 0. Leaving this field set to a 1 results in a fault code of 364 being logged against a DS1 circuit pack continuously.

The following are examples of DS1/DMI facility specifications. First, figure B-1, Incorrect Translations (Procedure 260), shows incorrect translations. Figure B-2,Correct Translations (Procedure 260), shows correct translations. Later examples will show options that will work but cause irrelevant fault codes to be logged in maintenance. Each application requires appropriate option selections based on characteristics of the equipment used and the desired requirements.

OPTIONS:

●ESF FRAMING

●PER-CHANNEL SIGNALING

●ROBBED-BIT SIGNALING

●ZCS

DS1 OR DMI	TRANSMISSION FACILITY
INTERFACE	(NO COMMUNICATION)

OPTIONS:

●D4 FRAMING

●PER-CHANNEL SIGNALING

●ROBBED-BIT SIGNALING

●ZCS

DS1 OR DMI

INTERFACE

THIS PROBLEM WILL CAUSE A RED ALARM STATE (LOSS OF FRAMING).

Figure B-1.Incorrect Translations (Procedure 260)