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Type
Source
Abbreviated
(N) ................ 3in7 (1110000) ............. Loopback data from network toward network in the HTU-R
(N) ................ 4in7 (1111000) ............. Loopback data from network toward network in the HTU-C
(N) ................ 2in6 (110000) ............... Loopback data from network toward network in first HRE
(N) ................ 3in6 (111000) ............... Loopback data from network toward network in second HRE
(C) ................. 6in7 (1111110) ............. Loopback data from customer toward customer in HTU-C
(C) ................. 5in7 (1111100) ............. Loopback data from customer toward customer in HTU-R
(C) ................. 4in6 (111100) ............... Loopback data from customer toward customer in first HRE
(C) ................. 5in6 (111110) ............... Loopback data from customer toward customer in second HRE
Wescom
(N) ................ FF1E ............................. Loopback data from network toward network at HTU-C
(C) ................. 3F1E ............................. Loopback data from customer toward customer at HTU-C
(N) ................ FF04 ............................. Loopback data from network toward network at HRE 1
(N) ................ FF06 ............................. Loopback data from network toward network at HRE 2
(C) ................. 3F04 .............................. Loopback data from customer toward customer at HRE 1
(C) ................. 3F06 .............................. Loopback data from customer toward customer at HRE 2
(N) ................ FF02 ............................. Loopback data from network toward network at HTU-R
(C) ................. 3F02 .............................. Loopback data from customer toward customer at HTU-R
(N) ................ 1in6 (100000) ............... Loopback data from network toward network at HTU-R
(N) ................ FF48 (ESF-DL) ............ Loopback data from network toward network at HTU-R
(N/C) ............. 1in3 (100) ..................... Loopdown everything
(N/C) ............. FF24 (ESF-DL) ............ Loopdown everything
Notes: The Source column indicates which side of the interface the control codes are sent from. For example, an "(N)"
indicates a network sourced code while a "(C)" indicates a customer sourced code.
All codes are inband unless labeled ESF-DL
All codes listed above must be sent for a minimum of 5 seconds in order for them to be detected and acted upon.
ESF Arm Sequence
0001 0010 1111 1111
for four repetitions
Race-free operations of the HDSL element arming
and Smartjack loop-up is accomplished as described
for the in-band code. For example, the ESF arm
sequence causes the Smartjack to loop-up and all of
the HDSL elements to move from the disarmed state
into the armed state. All other ESF data link control
code sequences are ignored in the disarmed sate.
Armed State
In the armed state, the HDSL system element
continues to be transparent to data flow. However,
the in-band data flow is monitored for the activation
and disarming sequences. The ESF data link is
monitored for the disarming sequence.
All other in-band and ESF data link control code
sequences are ignored in the armed state. An
arming timeout value causes automatic return to the
disarmed state.
Transition from Armed to Loop-up State
An in-band control code sequence is used to
command a specific HDSL element to move from
A-4
Table A-2. HDSL Loopback Control Codes
Code
Name
Section 61246045L1-5, Issue 2
the armed state into the loop-up state. Each HDSL
element has a unique 16-bit activation control code
sequence as shown in the following example:
HTU-C Activation Sequence
101 0011 1101 0011
HTU-R Activation Sequence
1100 0111 0100 0010
The designated HDSL element will loop up after
receiving the proper activation sequence.
Transition from Armed to Disarmed State
All HDSL elements can be commanded to move
from the armed state into the disarmed state by the
standard 5-bit in-band disarming sequence used for
NIU Smartjack loop-down. Each HDSL element
must disarm after receiving the following code for
five seconds:
Disarm Sequence
11100
The disarming process ensures race-free operation
of HDSL element disarming and Smartjack
loop-down. Duration of the disarm sequence may
61246045L1-5B
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