The Fairfax press is reporting that some BlackBerry users with models purchased originally from other carriers will get a rude shock come August, when the telco giant will be shutting down a portion of its NextG network.

Telstra currently runs it’s 3G network on two bands – 850MHz and 2100MHz. The 850 network allows for better range, clarity and data throughput. The 2100 range was operated in a joint agreement with 3, who were sold in 2011 to Vodafone. Optus and Vodafone run their 3G network on the 2100Mhz band,

Most handsets sold in the last 3 years are dual-band, capable of running on either network. For regular users, this will mean that some handsets purchased originally from Optus, 3 or Vodafone that have since been transferred to Telstra’s network will not receive 3G data speeds after August. But the issue is particularly pressing for users of BlackBerry devices, which have long been the preferred handset for fleet customers- large businesses purchasing dozens or hundreds of handsets to deploy to field workers. The downgrade will render entire batches of company IT equipment more or less worthless.

The upside is that this will free up space and network equipment for Telstra’s 4G offering, operating  on an 1800MHz band that promises superior speeds to even ADSL and Cable connections (though real-world speeds will likely be lower, with data allowances and stability still a concern). Optus and Vodafone are also developing new networks designated as 4G.

Optus (1300 137 897) and Vodafone (1300 106 571) have not announced any plans to move away from the 2100MHz band, and currently offer a wide range of phones and plans able to take advantage of both bands. Newer BlackBerry models, including the Bold 9900 and Torch 9860, are multiband phones capable of working on Telstra’s 850MHz band.