Around ten thousand of New Zealand’s most remote households connect to the public switched telephony network (PSTN) via customer multi-access radio (CMAR). Although copper loops connect up these neighborhoods of between ten and sixty houses, the loops are disconnected from major fibre optic backbones because of the cost of running cable across rough territory. These systems provide excellent voice service, but data service is limited to 14,400 bits per second – or around 0.1% of the capacity of a modern ADSL connection.

In the recent demerger of Telecom New Zealand, the CMAR network has gone to Chorus, as indicated the Asset Allocation Plan (PDF).

The diagram below illustrates a typical CMAR topology. It shows a local copper loop linking houses, an outstation linking the loop to a radio tower, and a radio linking network connecting the system back in to a regional centre with fibre optic network access.

The Government’s Rural Broadband Initiative (RBI) misses most of these remote neighborhoods. Schools connected to the telephone network via CMAR are largely covered by the RSBI, the Remote Schools Broadband Initiative (PDF), and are likely to receive coverage via satellite or local wireless providers.

The map below shows all CMAR links licensed as of December 2011, with data extracted from MED’s Spectrum Search Lite database. Links are colored by bandwidth licensed, so it is likely that darker links serve more customers than lighter links. It’s these areas in particular the government and groups like InternetNZ and TUANZ should be looking at when working to bridge the Digital Divide.

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Exploring the potential for providing broadband to remote customers serviced by CMAR is one part of a larger project Telco2 is working on for Hawkes Bay electrical lines trust Centralines.