ADTRAN 25 manual

_ M A I N T E N A N C E

Each of the 12 universal carrier slots has 48 pins on the backplane for connection to station and trunk ports. The 48 pins are divided into eight groups of 6 pins each, one group for each port circuit. Lead designations consist of the lead name suffixed by the group number (for example, TA.2, RA.2). Specific functions depend on the type of port CP. Table 4-Dprovides the 25-pin connector to backplane pin designations.

Typical backplane problems include power supply failure, sudden failure of one or more CPs or system troubles that cannot be isolated to a specific maintenance unit.

Backplane troubles are usually caused by bent or broken pins. A visual inspection of the backplane may be adequate to determine if pins are bent or broken. This inspection may require removing one or more CPs

Backplanes cannot be repaired in the field. When a backplane is faulty, the entire cabinet (but not the CPsin the cabinet) must be replaced.

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