Functional Description
150-512-100-03, Revision 03
10
September 25, 1998
HRU-512 List 1
L
OCAL
AND
L
INE
P
OWER
The HRU-512 List 1 can be powered from either the line (over the HDSL
cable pair) or from a local -48 Vdc power supply. It always chooses the local
-48 Vdc power supply if present. It defaults to line power in the absence of
local power. The HLU determines the power state of the HRU before
applying line power. If the HRU is powered up, the HLU does not turn on the
line power. If the HRU is not powered up, the HLU turns on the line power.
When locally powered, the HRU-512 List 1 provides 14 mA (long loop) to
16 mA (short loop) of metallic sealing current towards the HLU, when the
HRU-512 List 1 is locally powered. Jumper JP2, located on the
HRU-512 List 1 (shown in
), and switch SW5 located on the HLU,
may be configured by the user to either enable or disable the metallic sealing
current capability.
To enable the sealing current capability when the HRU-512 is locally
powered, the following two steps must be performed:
1
At the HLU, set switch SW5 to the LOCAL position.
2
At the HRU-512 List 1, connect JP2 across both terminals.
Sealing current from the HRU-512 will only be provided if JP2 is jumpered
across both terminals when the HRU-512 List 1 is locally powered.
To configure the system for the HLU line powering:
1
At the HLU, set switch SW5 to the LINE position.
2
At the HRU-512 List 1, connect JP2 across just one of the two terminals.
These are the factory defaults for both units.
