ADTRAN D4 U-BR1TE V warranty IDSL/DDS Trouble Codes 2B Leased Mode Operation

During a remote end initiated loopback the system transmits ASC 9Eh toward the network, indicating an out-of-service condition generated by the remote end, as shown in Figures 10 and 11.

All IDSL/DDS system latching loopbacks, whether initiated by the IDSL DCU-R craft interface, LBK pushbutton, CO, or from a remote Test Center, can be released by sending 35 DDS loop down TIP bytes <X0111010> (Where X is a “don’t care” bit). All existing latching loopbacks will also be disabled by pressing the LBK pushbutton on the CO or remote unit.

NOTE

The remote end test feature is only supported when the upstream U-BR1TE is an ADTRAN D4 or Series 5 U-BR1TE with DDS Loopback capability. Other U-BR1TEs will ignore the loopback command sent by pressing the IDSL OCU-R LBK button.

IDSL/DDS Trouble Code

The IDSL/DDS system provides a quick diagnosis in the case of a circuit condition where continuity is broken. The trouble code type received by a tester determines whether the open condition is occurring on the local loop or at the customer premises. In the event of a 2-wire DSL loss of signal, loss of sync, or open condition caused by an open conductor or disconnected 2-wire loop, the U-BR1TE V transmits a MUX-Out-of-Sync trouble code (MOS 9Ah) into the network as shown in Figure 12. During a similar out-of-service condition at the customer premises, the IDSL OCU-R transmits Abnormal Station Code (ASC 9Eh) upstream toward the network as shown in Figure 12.

	Channel Bank	Customer Premises
		Open 2-wire Loop
MOS 9Ah	U-BR1TE	IDSL OCU-R	DSU
	IV
	Channel Bank	Customer Premises
		Open 4-Wire Customer
		Interface
ASC 9Eh		ASC 9Eh
	U-BR1TE	IDSL OCU-R	DSU
	IV

Figure 12. IDSL/DDS Trouble Codes

2B Leased Mode Operation

The U-BR1TE V is deployed in 2B leased line operation to provide DDS/Frame Relay services to ISDN equipment. By using the 2-wire ISDN interface for 128 kbps data rate, the U-BR1TE V Leased Mode Operation allows pair savings over traditional DDS deployment. DDS/Frame Relay support allows loopback testing to be performed across the ISDN transport system in this configuration.

The U-BR1TE V will decode DDS latching loopback sequences coming from the carrier into eoc loopback commands usable by traditional ISDN equipment. See Figure 13 for various U-BR1TE V DDS 2B Leased Mode arrangements. In a SLC-96 network the U-BR1TE V units will operate in both 2B+D or 2B mode. Both units must be in the same mode.

Loopback Operation

To enable detection of DDS latching loopbacks, the ADTRAN U-BR1TE V must be provisioned as an LT- like device in leased 128 kbps (2B) mode of operation.

When B1 and B2 are enabled, data on both channels are looped in response to a DDS latching loopback sequence detected on channel B1. The U-BR1TE V will respond to a DS0 latching loopback intended for DS0 #1. Loopback commands intended for DS0 #2 and greater are re-mapped to ISDN eoc loopback commands addressed to the appropriate unit.

The U-BR1TE V will map a CSU latching loopback sequence to an ISDN eoc NT1 loopback. Figure 13 shows the DDS latching loopback commands that will loop each unit.

NOTE

Only the B1 channel will detect the DDS loopback sequences for activation and deactivation of DS0 and CSU latching loopbacks. All standard U-BR1TE units between the ADTRAN U-BR1TE V and the NT1 device must have the D-channel enabled in order for loopbacks to be processed beyond the U-BR1TE V.

61104020L4-5C Section 61104020L4-5, Issue 3 13