HDSL System Testing
61247004L1-5A
33
Figure 20. HDSL Loopbacks
HTU-C Network-Side Loopback
HTU-R Customer-Side Loopback
HTU-C Customer-Side Loopback
HTU-R Network-Side Loopback and/or HTU-R NIU Loopback
HR Customer-Side Loopback
HRE Network-Side Loopback
X = Signal Inactive
HRE #2 Network-Side Loopback
HRE #2 Customer-Side Loopback
HTU-R Bilateral Loopback
LOCAL
LOOP
DS1
AIS
HTU-C
HTU-R
DS1
AIS
DSX-1
HTU-C
HTU-R
HRE #1
HRE #2
X
X
DS1
AIS
HTU-C
HTU-R
HRE #1
HRE #2
X
DS1
AIS
HTU-C
HTU-R
HRE
X
DSX-1
DS1
AIS
HTU-C
HTU-R
HRE
X
LOCAL
LOOP
DS1
AIS
HTU-C
HTU-R
X
LOCAL
LOOP
DS1
AIS
HTU-C
HTU-R
X
DSX-1
LOCAL
LOOP
DS1
HTU-C
HTU-RX
DSX-1
LOCAL
LOOP
AIS
DS1
HTU-C
HTU-R
X