ACCULINK 336x E1 NTU
4-18 December 1996 3360-A2-GB20-20
Starting a DTE Loopback
The DTE Loopback command (DLB) loops the
received signal on the G.703 DTE port back to the DTE
without change. All ones are inserted into the DS0
channels allocated to the G.703 DTE port.
A DTE loopback can be activated and deactivated
based on the state of an external contact on the G.703
DTE port. If this option is enabled with the DTE Interface
configuration option Extrn DLB, closing the contact
activates a DLB. The DLB remains active until the
contact is opened. Refer to the G.703 DTE Interface
section in Appendix D, Pin Assignments, for more
information.
NTU
DTE
(G.703) DLB HDSL
AIS
DTE LOOPBACK (DLB)
495-1476
0
To perform a DTE loopback,
1. From the top-level menu screen, select Test.
2. From the Test screen, select Lpbk.
F1
Test:
Rlpbk Lpbk Ptrns
F2 F3
3. From the Loopback screen, press the key until
the DLB selection appears on the screen.
F1
Loopback:
Abort LLB PLB
F2 F3
4. Select DLB.
F1
Loopback:
LLB PLB DLB
F2 F3
Test Started appears on Line 2. If a DTE
loopback is already in progress, the Already
Active message appears. If an invalid combination
of loopbacks is in progress, the error message
Invld Test Combo appears (see Table 4-9 for
valid loopback test combinations).
Starting a Repeater Loopback
The Repeater Loopback command (RLB) loops the
signal being sent to the network back to the G.703 DTE
and data ports. The signal is looped back as close to the
network interface as possible (after it has passed through
the framing circuitry of the E1 NTU). Therefore, framing
CRCs and BPVs are corrected. All ones are transmitted to
the network interface.
NTU
DTE
(G.703) RLB HDSL
AIS
REPEATER LOOPBACK (RLB)
495-1476
1
To perform a Repeater loopback,
1. From the top-level menu screen, select Test.
2. From the Test screen, select Lpbk.
F1
Test:
Rlpbk Lpbk Ptrns
F2 F3