Section 150-612-102
Revision 03
Page 7
SF
YELLOW LED indicating that framing pattern of
the signal being received at the HRU’s DS1
input is SF.
ERR
RED LED indicating a DS1 frame error has
occurred.
Note the FRM LED remains off if the HRU input
pattern is unframed or if the HiGain-2 FRMG
option is set to its unframed (UNFR) mode.
8.02 VHDSL.
The lower 40% of the front
panel addresses the following VHDSL
interface features.
OK
GREEN LED that flashes while the VHDSL Loop
is synchronizing with the HLU. A solid green
state indicates that Loop is properly
synchronized with the HLU.
MAR
YELLOW LED indicating that the HRU’s S/N
MARgin on the VHDSL Loop has dropped
below the user defined margin threshold value.
This option is set at the HLU in the System
Settings menu of the maintenance interface
system at the RS-232 maintenance port.
ES
RED LED that flashes ever second in which at
least one VHDSL CRC error is detected.
9. OPTIONS
9.01
The HiGain-2 List 2 system has several
special loopback (SPLB) options that
are set at the HLU. Refer to practice # 150-611-
100 for more details. The HRU also has three
user options set by switches located at the back
of the unit as shown in Figure 4. Each switch
has two settings as follows (refer to the block
diagram in Figure 2 for details):
•
I-CPE
0*: Sets the CPE current to 0 mA..
60: Sets the CPE current to 60 mA to power an
external NID.
•
TLOS-LB
DIS*: A loss of the T1 XMT signal from the CPE
causes the HLU to transmit the AIS signal
towards the DSX-1 and does not cause the HRU
to enter its logic loopback state.
EN: A loss of the T1 XMT signal from the CPE
forces the HRU to enter its logic loopback state
(TLOS in Figure 5). While in this loopback
state, the HRU transmits the AIS signal towards
the CPE and returns the Network signal back to
the Network. The HLU displays the message
TLOS in its 4 character front panel read-out.
This condition remains until a valid T1 signal is
received from the CPE or until a loopdown
command is issued. Note that once the TLOS
initiated loopback has occurred, it can not
reoccur until the CPE T1 signal has been
reapplied and then removed. This “latching”
feature prevents the HRU from oscillating into
and out of TLOS loopback when a loopdown
command is issued in the absence of a T1
signal from the CPE.
Figure 4. HRU-612 Manual Switches