ADC H4TU-C-319 List 1 Line Unit Manuel D’Utilisation

Pin H on the card-edge connector (see 

) is the H4TU-C-319 System Alarm output pin. The 

following notes apply to Pin H:

Pin H replaces the Local Loss of Signal (LLOS) on normal high-density (3192) repeaters.

The normally floating output of Pin H can connect to pin 1 of the 1184 or 3192-9F Alarm Card in position 29 
of the High Density (HD) shelf.

The H4TU-C forces pin H to +5Vdc (maximum of 10 mA) for a system alarm condition. Pin H then remains 
at +5 Vdc for the duration of the alarm condition.

If the Wescom 1184 Alarm Card is installed in the shelf, its LOS LED lights for every minor alarm 
(MNRALM). 

The H4TU-C Status LED flashes red for the duration of a system alarm condition.

Setting the ALM option to DIS only prevents the system alarm bus on Pin H from being activated for a system 
alarm event. The Status LED still flashes red and the ALRM message still displays.

 shows the pinout for the craft port connection and its connection to a DB-9 or DB-25 connector on a 

maintenance terminal.

RD (Receive Data)

TD (Transmit Data)

GND