150-402-102-01, Revision 01
Product Overview
HRU-402 List 2
July 27, 1998
9
Table 3.
Rear Panel Components
Name
Function
Sealing Current- Rear Unit Switch S1
DIS
(a)
(a.) Denotes factory default setting.
Prevents the flow of simplex sealing current over the HDSL pairs towards the
upstream unit.
ENA
(b)
(b.) This simplexed sealing current is polarity sensitive and will not flow if the
HDSL loops adjacent to the HRU are reversed. Reversed loops are indicated
by a CHREV message in the ALARMS line of the SPAN STATUS
Maintenance screen
Allows the flow of simplex sealing current over the HDSL pair towards the
upstream unit. The local power option LPWR must also be set to ENA to allow
sealing current to flow.
Local/Line Power- Rear Unit Switch S1
DIS
(a)
Forces the HRU to its Line Power mode where it obtains its power from the
upstream line unit over the HDSL pairs.
ENA Forces the HRU to its Local Power mode where it obtains its power from the
-48V supply applied to its edge connector pins 35(-) and 17(+) when present.
If -48V of local power is not present, the HRU reverts to its Line Power mode.
