Verilink PRISM 3001 (34-00186) Product Manual - Manual (Page 45)

Maintenance Screen 4-11
4 NET MLB: The network maintenance loopback command loops data at the T1
DTE port back toward the network (passes network data to the DTE and return
data to the network). MLB affects only network channels assigned to the T1 DTE.
5 DTE MLB: The T1 DTE maintenance loopback command loops all network data
back toward the DTE ports at the network interface. Data is passed through to the
network. It is advisable to set T1-NET Timing to INTERNAL rather than
NETWORK when this loop is enabled.
6 DTE LLB: The T1 DTE line loopback command loops data received at the T1
DTE interface back toward the T1 DTE (all DS0s are returned to the T1 DTE
port). The T1 DTE data is also passed to the network.
FAR PLB: The far payload loopback command sends loop codes to the far-end
unit to force it into a network payload loopback mode.
FAR LLB: The far line loopback command sends loop codes to the far-end unit to
force it into a network line loopback mode.
T1 Unloop
Pressing Enter on this field takes down the specified loop from the currently
selected element.
7 Port Loop: The Port Loop field is used to loop a high-speed DTE port at the near
or far end. Far end loops use V.54 loop codes to activate, therefore, the V.54
function must be enabled (refer to Port Parameters on page 4 -19). high-speed port
loops are bidirectional. The loop is chosen by toggling the spacebar.
Figure 4-7 Loopback Diagrams
Normal Operation
Network Interface
To Network
From Network
RJ-48C
Framer/Deframer Multiplexer Receivers/Drivers
Receivers/Drivers
BERT Generator/
Detector
DTE (EIA-530 or V.35)
(100' max.)
Framer/Deframer
DTE (DSX1)
RJ-48C
DSX1, 1'-655'
to cross-connect
From
NET
To
NET
To
NET
From
NET
To
Ports
From
Ports
5
4
2
1
Network LLB
Network Interface Framer/Deframer Multiplexer Receivers/Drivers
Receivers/Drivers
BERT Generator/
Detector
EIA-530 or V.35
(100' max.)
Framer/Deframer
DTE (DSX1)
RJ-48C
DSX1, 1'-655'
to cross-connect
From
NET
To
NET
To
NET
From
NET
5
4
2
1
To Network
From Network
RJ-48C
To
Ports
From
Ports
NET
LLB
1
2