Paradyne 317x E1 manual Local Loopback Tests, Valid Loopback Combinations

Maintenance

Local Loopback Tests

The Local Loopback tests enable you to conduct circuit testing and fault isolation for the digital line. The supported local loopback tests are:

•Line Loopback (LLB)

•Payload Loopback (PLB)

•DTE Loopback (DLB)

•Repeater Loopback (RLB)

•Data Channel Loopback (DCLB)

•Data Terminal Loopback (DTLB)

NOTE

DLB does not appear when the DTE Drop/Insert interface is disabled.

The Line Loopback command can be activated and deactivated in response to commands received over the network interface. The Network Interface configuration option NET LLB controls whether the E1 DSU/CSU responds to the commands transmitted on the network interface to initiate LLBs (see Appendix C, Configuration Options).

The data port configuration option NET DCLB controls whether the E1 DSU/CSU responds to inband V.54 commands to initiate DCLB for that port (see Appendix C, Configuration Options).

Local loopback tests can be aborted (Abort Command) at any time.

No more than two local loopbacks can be active at any one time. An additional restriction prohibits certain loopbacks from running at the same time. Valid loopback combinations listed in Table 4-8 are identified by YES.

Table 4-8

Valid Loopback Combinations

	LLB	PLB	DLB	RLB	DCLB	DTLB
LLB	N/A	NO	YES	YES	NO	YES
PLB	NO	N/A	YES	NO	NO	YES
DLB	YES	YES	N/A	NO	YES	YES
RLB	YES	NO	NO	N/A	NO	YES
DCLB	NO	NO	YES	NO	YES	YES
					(on separate	(on separate
					ports)	ports)
DTLB	YES	YES	YES	YES	YES	YES
					(on separate	(on separate
					ports)	ports)

3170-A2-GB20-20 December 1996 4-15