ADTRAN 1200068L1 HS Series User Manual page 20

Network Interface
T 1
16
sal, the DDS CSU (connected to the OCU DP over a 4-
wire loop) should loop data back toward the NI.
The OCU loopback loops the data mapped to the
OCU DP back toward the network interface of the
controller. Using the loopback in conjunction with an
external BERT driving the Network Interface, will exer-
cise the entire data path from the Network Interface
(NI) through the OCU DP option module and back out
the NI. See Figure 4, Diagram of Loopbacks.
TSU 100
(NI)
(Controller)
PRT/LCL
Figure 4. Diagram of Loopbacks
The PRT/LCL bidirectional loopback loops the
data mapped to the OCU DP back to the network
interface of the controller. It also loops data from the
DSU/CSU back to the DSU/CSU. If the DSU/CSU is
capable of sending a test pattern, it can be used with this
loopback to verify integrity of the 4-wire DDS loop.
To deactivate the Loopback, OFF must be selected
under the 1.1 OCU DP submenu.
61200.068L1-1C
OCU DP
4-wire DDS
OCU
DSU/CSU
CSU
November 1996