Investigation into the Mounting of the 3M BRCP Splitter Blocks in the Whisper Cabinet 24 October 2008

Chorus Confidential 2 Background The Commerce Commission’s draft determination for the sub-loop services proposed the use of splitters in HDP blocks, as opposed to the DSLAM, on the basis that it would eliminate the need for splitters to be located within the Rackprints of Telecom and our external customers (draft determination, paragraph 60). The aim of this test was to investigate the feasibility of mounting splitter blocks in the termination bay of the existing single bay and double bay Whisper cabinets. The cabinets are designed around the Krone LSA+ NT 10 pair IDC termination block (or equivalent). This is a compact block. The cable runs behind the vertical block. The jumpering runs between the blocks. The blocks are 122.5mm wide (when viewed from the front). The termination bay of the cabinet contains 4 verticals. The space between the verticals is reduced to the minimum required to mount jumper rings. Overall, the design of the termination bay of the cabinet is very space efficient. We obtained 3M BRCP integrated splitter blocks, which would allow splitters on the HDP blocks. A practical exercise was then undertaken at Eaton to look at the feasibility of mounting and using these blocks in the single bay Whisper cabinet. This study was just to address the feasibility of mounting the 3M blocks, NOT: The effect on the number of terminations The additional costs associated with the 3m blocks and splitters

Chorus Confidential 3 Conclusion The 3M BRCP splitter blocks can NOT be successfully integrated into the existing single or double bay Whisper cabinets. The existing cabinet design is based around a more compact block and there is insufficient width in the cross connect chamber (termination bay) to allow the wider 3M block to be mounted and to maintain functionality.

Chorus Confidential 4 The 3M BRCP Splitter Block The 3M splitter block is designed to swivel on the front edge to give access behind the block to mount the splitters as required The 3M splitter block is 133mm wide and when opened to install or maintain the splitter units it requires a width of 185mm. The latch mechanism is shown in the picture below and requires the plastic tongue to be pulled out to release The block can be mounted as either left or right hand opening Exchange tie cable jumper connections Distribution cable jumper connections DSLAM tie cable connections Plug in splitters Hinge point Latching mechanism

Chorus Confidential 5 Mounting in the Left hand vertical The normal position for these blocks (functionally) would be the left and 2 nd most left verticals For the left vertical the jumpers are run down the right hand side this means the opening latch is on the left side To obtain access to the opening latch was difficult and required the blocks to be mounted offset as shown in the pictures This offset means the block extends into the jumper field and will be blocked by the jumper rings. When the block is opened this will be even more of a problem Note – the right hand vertical has the same issues Block position to allow hand access showing the distance to be moved 3M block mounted in standard position Difficulty in getting hand in to release the block Existing Krone terminations Note the overlap with the jumper ring Block position to allow hand access

Chorus Confidential 6 Mounting in a centre Vertical In the pictures a foam strip has been used to represent the jumper field. It must be noted that while jumpers are generally run “loose” they invariably tighten up due to the effects of other jumpers and press to the edge of the jumper rings The top picture shows that when opened the “latch” edge has to pass through the jumper field, this is after a technician has managed to get their fingers through the jumper field to release it. The bottom picture demonstrates how the hinged edge has to also push into the jumper field when opened. Foam strip represents the jumper field Note the overlap when the block is opened Foam strip represents the jumper field Note the overlap when the block is opened

Chorus Confidential 7 Other Observations Cable runs The current Krone connectors have the cable feed behind the blocks, ie between the blocks and the back of the mounting bracket. This contrasts with the 3M block which requires the cable to run along side the block. This means that the Krone and 3M blocks can not be mixed and matched down a vertical. If both types of blocks are required on a vertical then the 3M blocks must be downstream of the Krone blocks in terms of the cable run. Flexibility With the current Krone configuration maximum flexibility is maintained to allow future demand to be catered for even if it is not in the order expected. This would be reduced if a level of 3M blocks were introduced Double Bay Whisper The same problems exist with the double bay whisper cabinet. In fact it would be more challenged as it has a smaller cross connect chamber. In field retrofit While it has been shown that it is not functionally feasible to fit the 3M blocks into the current cabinet it is also noted that due to the different methods of cable feed that it would not be practical to retrofit in the field.