Verilink PRISM 3111 (34-00242) Product Manual - Manual (Page 64)

56 C HAPTER 4: T ERMINAL I NTERFACE
DTE LLB The T1 DTE LLB 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 LLB This field appears when you set the T1 Loop to Far LLB. It determines if framed
or unframed loop code is sent to the far end unit. Valid options are framed and
unframed.
Some devices require framed loop code while others require unframed loop code.
This is a vendor specific requirement.
T1 Unloop Pressing takes down the selected T1 loop. Options are Net PLB, Far PLB,
Net LLB, Net MLB, DTE MLB, DTE LLB and Far LLB.
Port Loop This field is used to loop high speed data port from the network back to the
network and data from the DTE back to the DTE. The Port Loop may be activated
by receipt of inband V.54 fractional loop code or by this field. The Port Loop will
only have ports with channels allocated to them as selections. Ports without
channels allocated appears as blank fields.
On the PRISM 3112, each data port loops independently of the other. You activate
a Port Loop on the remote end unit through this field or by the front panel test
switch (non-LCD unit). The test switch can be used to activate a remote Port 1
loop if configuration Switch S1-7 is set to Inband V.54. Either method causes the
unit to transmit inband V.54 fractional loop code toward the network in the port’s
bandwidth.
Figure 4-7 Bidirectional Port Loop
Port Unloop Pressing takes down the specified loop from the currently selected port.
T1 DTE
LLB
Network Interface Framer/Deframer
Framer/
Deframer
Multiplexor Receivers/Drivers
Receivers/
Drivers
BERT Generator/
Detector
From
Ports
To
NET
From
NET
To
Ports
From
NET
To
NET
DTE (DSX1)
(100' max.)
DTE Data Port
RJ-48C
RJ-48C
DSX1, 1'-655'
to cross-connect
1
2
4
5
4
5
1
2
To Network
From Network
✍
Network Interface Framer/Deframer
Framer/
Deframer
Multiplexor Receivers/Drivers
Receivers/
Drivers
BERT Generator/
Detector
From
Ports
To
NET
From
NET
To
Ports
From
NET
To
NET
DTE (DSX1)
(100' max.)
DTE Data Port
RJ-48C
RJ-48C
DSX1, 1'-655'
to cross-connect
1
2
4
5
4
5
1
2
To Network
From Network
DTE
Near/Far