comparator 84 the alarm card 90 illustrated in fig1 b and 1c is a pcba assembly which affixes to the rear side of a uts backplane via the alarm card connector 18 on the alarm sub plane 16 the alarm card 90 mounts perpendicularly to the alarm sub plane and is supported by fasteners located on the uts side frame the alarm card interfaces include a 64 pin connector mounted on the local sub plane 16 used to terminate logic and monitoring signals and two rj 45 connectors used for customer input and output the alarm card 90 provides user trunk bypass and ringing cut off switches terminates connections to shelf and cabinet level alarm functions provides mounting space for a ringing generator dc to ac converter and provides power for a low voltage system modem further the alarm card 90 reports local shelf alarm conditions and adjacent shelf alarm conditions to the local sdu 24 the sdu 24 combines the alarm card data with link alarm information in overhead channels to the common control each alarm condition consumes a bit in one of four bytes to each of two shelves the eight bytes provide information as to power supply and temperature status user controls status pedestal status and system major and minor alarm loop back to both shelves system wide notification of four degrees of alarms i e critical major minor and trunk bypass occurring within the system is provide by four leds mounted on the power supply board s inserted in each shelf in the positions as illustrated in fig1 and 2 as previously illustrated in fig1 the uts shelf provides two slots for power supply boards the power supply boards used in the uts are approximately one.