ADC HiGain H2TU-C-202 User Manual page 28

Provisioning
Bipolar Violation Transparency (BPVT) Option. The H2TU-C-202 improves compatibility with Digital
Loop Carrier (DLC) feeder applications because of its ability to transmit T1 BPV occurrences between its T1
interfaces. This feature is required to support protection switching in DLC applications. Each DLC terminal must
be able to monitor the integrity of its Receive T1 payload and then switch to the protect line when the integrity of
the path drops below specific user selected limits. An essential requirement of this feature is the need for each
DLC terminal to detect BPVs in its T1 input. Standard HDSL systems correct T1 BPVs at the input and therefore
prevent them from being detected by the DLC terminals to which they are connected. The H2TU-C-202 and its
associated remote units remove this limitation and become BPV transparent by detecting and counting input BPVs
at each end and then by replicating them at the T1 output port of the distant end.
The BPV count is converted into BPVs at the distant end during the following second at a rate of 1 BPV every
128 T1 bits up to a maximum of 12000 (BER=7.7 x 10
exceeds the maximum 10
DS1 BER (DBER) Option. The DS1 BER alarm occurs when any of the DS1 or DSX-1 performance
monitoring parameters listed in
through 11:59:59 PM. These thresholds correspond to a 10
or when Master Clear is selected.
H2TU-R DS1 Frame Conversion (CONV) Option. Frame format conversion is only applicable to the
remote H2TU-R, but selectable by the H2TU-C or H2TU-R. This option enables the network to be ESF, which is
used to embed SPRM or NPRM into the datalink towards the network. During conversion, frame bit errors are
regenerated to ensure transparency.
The HDSL2 system attempts to find ESF or SF framing or determines that no framing exists. The DS1 framing is
then synchronized with the HDSL2 frame. If the framing is lost, the system generates an Out-of-Frame (OOF)
defect which results in UAS-P. As a result, the system reverts to frame search mode.
This option has the following settings:
• OFF: No frame conversion takes place. All framing issues are determined by the FRMG option settings of
AUTO and UNFR.
•
ACON: This is the automatic conversion setting. If the system detects ESF from the network and SF from the
CPE, it automatically converts the CPE SF to ESF towards the network as well as the network ESF to SF
towards the CPE.
Upon power-on-reset, after loopdown, or after changing the frame conversion option, the framing needs to
be re-established before a complete conversion takes place. If there is a failure condition (LOS, AIS, or LOF)
during steady state, the previous conversion state is maintained to ensure continuity when the system returns
from the failure condition.
If SF is received from the network, the H2TU-R forces an ESF towards the network for about 1.5 seconds.
This signals to the far-end PM-NIU at the network boundary that frame conversion is requested. If the far-end
PM-NIU is capable of conversion, it changes the framing to ESF. If not, then the H2TU-R reverts to SF and
does not apply any conversion.
If an ESF is received from the CPE, it is passed on to the network, and the network's inbound framing is
passed on to the CPE.
20
-3
BER required by most DLC systems.
Table 7 exceed the counts shown for the 24-hour period between 12:00:00 AM
Table 7. DS1/DSX-1 24-hour PM Threshold
Parameter
CV-L (BPV)
ES-L, ES-P, PRM, PDVS-L
SES-L, SES-P
UAS-P, UAS-L
April 21, 2000
-3 ). This maximum rate is more than adequate since it
-6
BER. All PM counters clear to zero at 12:00:00 AM
Threshold Count
133,400
648
100
10
152-202-115-04, Revision 04
H2TU-C-202 List 1E