ADTRAN SLC-5 User Manual download pdf (Page 11)

Section 61102040L4-5, Issue 261102040L4-5B

DS0 DP Loopback

eoc

Remapping

Upon receipt of subsequent DS0 DP loopback codes

when the D channel is disabled, the U-BR1TE III

remaps the subsequent DS0 DP loopback sequences

into the respective ISDN eoc loopback messages.

This capability will permit all downstream ISDN D

channel enabled U-BR1TEs, U-Repeaters, and

TRISDN elements to respond to standard DDS DS0

DP loopback commands via the ISDN eoc as shown in

Figure 7.

NOTE

For DDS circuits with the D channel disabled,

all tandem U-BR1TE elements should be

ADTRAN U-BR1TEs with DDS Loopback

Capability for remote end test operation (OCU)

to function properly. See 2B in Figure 6. In D

channel disabled applications, older non-DDS

vintage U-BRITEs may not pass the OCU

latching loopback sequence to the IDSL OCU-R.

Upon receipt of an OCU latching loopback sequence

the U-BR1TE III passes the OCU sequence in-band

downstream to the IDSL OCU-R. U-BR1TE IIIs do

not respond to the CSU latching loopback command

but simultaneously passes it through to the CSU/DSU

while mapping the NT1 eoc address. The IDSL

OCU-R reverses sealing current on its 4-wire AMI

DDS interface to place the customer CSU into

loopback upon receipt of the CSU latching loopback.

The following data sequence enables the DS0 DP,

OCU, and CSU latching loopbacks:

1. Minimum of 35 transition in progress (TIP)

bytes (X0111010).

2. Minimum of 35 loopback select code (LSC)

bytes: DS0 DP (X0000101), OCU (X1010101),

CSU (X0110001).

3. Minimum of 100 loopback enable (LBE) bytes

(X1010110).

4. Minimum of 32 far-end voice (FEV) bytes

(X1011010).

If the U-interface of the U-BR1TE III is not in sync,

the unit transmits Mux-Out-of-Sync (X0011010)

upstream towards the network.

X Denotes Don’t Care bit - either a 1 or a 0.

Disabling DS0 DP, OCU, or CSU latching loopback

sequence:

1. Minimum sequence of 35 TIP bytes.

Front Panel Tests

The valid front panel tests in leased modes are ADR1,

CRTX, LPTX, and LPBK for all circuit positions.

NT1, ADR1-ADR6 loopback tests are valid for the

LULT mode only. ADR2 would be used to test a

U-Repeater or ADR2 and ADR3 would be used to test

TRISDN elements respectively.

Initiate Loopback at IDSL OCU-R

When used for DDS, the SLC-5 U-BR1TE may

initiate a loopback at the IDSL OCU-R. The in-band

latching OCU loopback code is sent to loop the IDSL

OCU-R when the NT1 address is selected on SW3.

To invoke the OCU loopback at the IDSL OCU-R, the

front panel test knob must be in the NT1 address

location.

ADTRAN U-BR1TE Bidirectional Loopback

In LULT mode, the ADTRAN U-BR1TE will execute

a bidirectional loopback when performing DS0 DP

loopback. Refer to Figure 8 for an illustration of the

bidirectional loopback.

Figure 7. IDSL/DDS Loopback Response

Test

Head

ISDN

RPTR

U-BR1TE

1B+D

IDSL

OCU-R

SLC-5

Loopback Response

DS0 DP #1

DS0 DP #2

DS0 DP #3

OCU

Test Set

IDSL OCU-R

ADTRAN U-BR1TE

Bidirectional

loopback

Figure 8. ADTRAN U-BR1TE Bidirectional

Loopback

1 2 ... 6 7 8 9 10 11 12 13 14

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ADTRAN SLC-5 User Manual Page 11

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