ADTRAN D4 U-BR1TE V

Section 61104020L4-5, Issue 3

61104020L4-5C

DS0 DP Loopback EOC Remapping

Upon receipt of subsequent DS0 DP loopback codes

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

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 8.

NOTE

For DDS circuits with the D channel disabled,

all tandem U-BR1TE elements should be

ADTRAN U-BR1TE Vs with DDS Loopback

Capability for remote end test operation to

function properly. See 2B in Figure 7. 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 V passes the OCU sequence in-band

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

not respond to the CSU latching loopback command

but simultaneously pass 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).

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

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

the unit transmits MUX-Out-of-Sync (X0011010).

Disabling DS0 DP, OCU, or CSU latching loopback

sequence:

1. Minimum of 35 TIP bytes.

or by pressing the front panel loopback button.

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.

All active in-band loopbacks may be disabled by

pressing the front panel loopback button once when a

test set is not connected to the bantam jacks.

Initiate Loopback at IDSL OCU-R

When used for DDS, the D4 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 SW2. To invoke

the OCU loopback at the IDSL OCU-R, press the Test

button with the front panel test knob in the NT1

address location.

Figure 8. IDSL/DDS Loopback Response

Test

Head

ISDN

RPTR

U-BR1TE

1B+D

IDSL

OCU-R

D4/SLC-96

Loopback Response

DS0 DP #1 DS0 DP #2 DS0 DP #3

OCU