150-512-100-03, Revision 03
Functional Description
HRU-512 List 1
September 25, 1998
9
Table 2.
Rear Panel Components
Switch
Setting
Function
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
Does not allow the HRU-512 List 1 to enter its logic loopback state
when a loss of the T1 XMT signal from the CPE causes the HLU to
transmit the AIS signal toward the DSX-1.
EN
Allows the HRU-512 List 1 to enter its logic loopback state when a
loss of the T1 XMT signal from the CPE causes the HLU to transmit
the AIS signal toward the DSX-1. While in this loopback state, the
HRU-512 List 1 transmits the AIS signal toward the CPE and
returns the network signal back to the network. The HLU displays
TLOS in its front panel display. This condition remains until a valid
T1 signal is received from the CPE or until the 3-in-5 in-band
loopdown command is issued. Once the TLOS initiated loopback
occurs, it will not reoccur until the CPE T1 signal has been
reapplied and then removed. This feature prevents the
HRU-512 List 1 from oscillating into and out of TLOS loopback
when a loopdown command is issued in the absence of a T1 signal
from the CPE. This TLOS option must never be enabled when the
HRU-512 List 1 is used with old line units that do not support this
feature. These older line units (List 6 and under) cannot loopdown
an HRU-512 List 1 that is in a TLOS loop-up state when they
receive the 3-in-5 in-band loopdown command.
RLEV
0
Configures the T1 RCV level to 0 dB. This sets the T1 output signal
level from the HRU-512 List 1 toward the NI to 0 dB. Use this
setting when the HRU-512 List 1 is not functioning as a NID but is
connected to an external NID. It allows the external NID to set the
appropriate NI level.
15
Configures the T1 RCV level to -15 dB. This sets the T1 output
signal level from the HRU-512 List 1 toward the NI level to -15 dB.
This setting is recommended when the HRU-512 List 1 functions
as a NID.
JP2
Allows the enabling or disabling of the sealing current. To enable,
connect JP2 across both terminals. To disable (default), remove
the jumper from the inner terminal and leave it attached to the
outer terminal only.
The 60 mA option can only be used if the HRU-512 List 1 is
locally powered.
