Installation
150-419-100-03>
18
September 25, 1998
HRU-419 List 1
Sealing Current (SCURR-JP1).
The two-prong male JP1 jumper allows
you to disable or enable the sealing current. The default is disable. To set the
sealing current, do one of the following:
•
To enable the sealing current, connect JP1 across both terminals using
the supplied female jumper block header.
•
To disable the sealing current, remove the jumper block header from both
terminals and insert it on the outer terminal for future use.
RLEV (JP2).
The RLEV switch (JP2) allows you to control the
configuration of the T1 Receive Level (RLEV). The default is 0. Setting
RLEV to 0 configures the T1 output signal level from the HRU towards the
Network Interface (NI) to 0 dB. This setting is recommended when the HRU
does not function as the NID but is connected to an external NID, as it allows
the external NID to set the appropriate NI level. Setting RLEV to -15
configures the T1 RLEV to -15 dB, and sets the T1 output signal level from
the HRU towards the NI level to -15 dB. This setting is recommended when
the HRU functions as the NID. To set the RLEV do one of the following:
•
To set the T1 output signal level to O dB, move the RLEV switch to 0.
•
To set the T1 output signal level to -15 dB, move the RLEV switch to -15.
TLOS-LB (JP3).
The TLOS-LB switch allows you to enable or disable the
configuration of the TLOS loopback. If you set TLOS-LB to disable prior to
entering a loopback state, a loss of the T1 XMT signal from the CPE causes
the HLU to transmit the AIS signal towards the DSX-1, and prevents the
HRU from entering its logic loopback state.
This simplexed sealing current is polarity sensitive and will
not flow if the two 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
shown in
.
The TLOS option must never be set to enable when the
HRU-419 is used with old line units that do not support this
feature. These older line units (List numbers lower than 6)
cannot loopdown an HRU that is in a TLOS loop-up state when
they receive the 2-in 5-in-band loopdown command.
