ADTRAN FT1 User Manual
Page 8
A-2
Section 61245211L1-5, Issue 1
61245211L1-5A
There is one loopback available to the FT1
Repeater. The FT1 Repeater Network loopback is a
digital loopback toward the CO as shown in Figure
A-4. The loopback is initiated by the DDS latching
loopback code for NEI Position 1 (N1000001). The
NEI Position 1 latching loopback is detected in the
primary DS0 of the FT1 circuit, the channel where
the FT1 DP is physically installed, to control the
looping of the FT1 circuit. When the FT1 circuit is
looped, all DS0s in use will be looped. The DS0s in
use will also be transmitted on to the customer.
This loopback is also initiated by the craft interface
or by the RLB push-button (when available) at the
FT1-DP.
There are two loopbacks available to the FNID. The
FNID network loopback loops the FT1 signal back
toward the network. The FNID CPE loopback loops
the FT1 signal back toward the customer.
The FNID network loopback is a digital loopback
toward the CO as illustrated in Figure A-5. This
loopback is initiated by the DDS latching loopback
code (NEI Position 1 - N1000001 for a non-
repeatered loop, or NEI Position 2 -N1000001 for a
repeatered loop), by the craft interface, or by the
RLB button at the FT1-DP. The NEI Position 1
latching loopback is detected in the primary DS0 of
the FT1 circuit -- the channel in which the FT1 DP
is physically installed -- to control the looping of the
FT1 circuit. When the FT1 circuit is looped, all
DS0s in use will be looped. The loopback keep
alive code will be transmitted to the customer.
The FNID CPE loopback is a digital loopback
toward customer premises as shown in Figure A-6.
This loopback is initiated by the craft interface.
When the FT1 circuit is looped, all DS0s in use will
be looped. The DS0s in use will be filled with all 1s
toward the network.
Figure A-4. FT1 Repeater Network Loopback
DSX-1
Interface
Central
Office
FT1 DP
D4
Channel Bank
FNID
HDSL
Local Loop
DS1
Interface
Customer
Premises
FT1
Repeater
Figure A-5. FNID Network Loopback
DSX-1
Interface
Central
Office
FT1 DP
D4
Channel Bank
FNID
HDSL
Local Loop
DS1
Interface
Customer
Premises
Figure A-6. FNID CPE Loopback
DSX-1
Interface
Central
Office
FT1 DP
D4
Channel Bank
FNID
HDSL
Local Loop
DS1
Interface
Customer
Premises