Verilink FrameStart FSD (34-00291.F) Product Manual - Manual (Page 35)

O p e r a t i o n 29
The received data is passed through to the DTE port. The NET LLB is
activated by detection of simplex current reversal.
Figure 4.6 Enable LLB for DDS CSU/DSU
Enable LLB (T1 CSU/DSU and FrameStart FSE only). (Line Loopback)
- As shown in Figure 4.7, the received network signal is looped back toward
the network with signal regeneration only (framing and CRC intact). During
the NET LLB, the DTE port is also looped. In T1 circuits, the NET LLB is
activated by receiving in-band or out-of-band loop code on the network
receive signal (E1 has no in-band loopcode enable) and by the front panel
LCD selection.
Figure 4.7 Enable LLB for T1 CSU/DSU and FrameStart FSE
Enable DLB (DDS/CSU/DSU only). As shown in Figure 4.8, the received
network signal is looped back toward the network in the local unit. This loop
is invoked by an in-band pattern.
Figure 4.8 Enable DLB
Network Framer / Receivers /
BERT
DTE
From
NET
To
NET
To
Port
From
Port
(Winchester-type
Connector)
Drivers Deframer Interface
Generator /
Detector
To Network
RJ-48C
From Network
Network Framer / Receivers /
BERT
DTE
From
NET
To
NET
To
Port
From
Port
(Winchester-type
Connector)
Drivers Deframer Interface
Generator /
Detector
To Network
RJ-48C
From Network
Network Framer / Receivers/
BERT
DTE
From
NET
To
NET
To
Port
From
Port
(Winchester-type
Connector)
Drivers Deframer Interface
Generator/
Detector
To Network
RJ-48C
From Network