Vodafone and Orcon customers are up in arms over an unidentified issue that is slowing down their ADSL2+ connections to ADSL1 speeds. The problem is affecting ISP customers served via Telecom Wholesale Unbundled Bitstream Access DSL, either from roadside cabinets or from telephone exchanges. Customers’ modems sync with the DSLAM at high rates, such as 22Mbit/s, but the actual speed achieved is only 7.6Mbit/s for downloads. Vodafone and Orcon LLU customers are not affected by the issue. Presently, the root cause of the problem hasn’t been identified. Customers using Vodafone-supplied Huawei modems report their download speeds are being capped to 7.6Mbit/s, despite syncing at high ADSL2+ rates. This has led some customers to suspect the DSL chip set inside the Huawei modems doesn’t function properly with Telecom Wholesale Alcatel DSLAMs. Yet other posters in the Vodafone customer forum are blaming misconfigured Telecom Wholesale DSLAMs for the problem. Many customers have gone through a great deal of effort to troubleshoot the problem, such as swapping modems and adding filters to their phone lines without success. However, some posters in Vodafone’s customer forum report that switching to a Telecom-supplied Thomson DSL modem restores connection speeds to ADSL2+ rates. Vodafone spokesman Paul Brislen says the telco is still analysing the issue and haven’t yet reached a conclusion as to what is causing the fault. Brislen doesn’t know how many customers are affected by the problem at this stage. Telecom Wholesale has been asked for comment on the issue and we will update the story as soon as it arrives.