As the deployment of ADSL2+ services is ramping up it is appropriate to review the microfilter requirements in order to ensure successful separation of voice and data streams sharing the same telephone line.

Microfilter compliance standards for ADSL1 services were initially simple and as a direct result microfilter performance issues were often encountered in the early stages of ADSL1 deployment. Compliance standards have evolved considerably since then and in order to satisfy these ACA requirements as well as Telstras own specified requirements, microfilter designs have become much more sophisticated.

New ADSL2+ services (up to 24Mbps) involve a much greater bandwidth that ADSL1 (up to 8Mbps) and older style ADSL1 microfilters were simply not designed to function correctly over the entire ADSL2+ bandwidth. Whilst ADSL1 microfilters may work adequately in certain conditions with ADSL2+ services, they are certainly not guaranteed to work over the complete ADSL2+ bandwidth and this leaves users susceptible to noise on their line which may affect both voice and data streams.

NetComm recommends that only ADSL2+ microfilters are deployed with ADSL2+ services. This will help to maintain high levels of customer satisfaction and reduce the chance of microfilter performance causing problems for customers leading to increased support calls.

NetComms EM1550 is an ADSL2+ splitter/microfilter that fully complies with all relevant ACA requirements, including AS/ACIF S041:2005 (ADSL2+), and also conforms to Telstras RCIT.0004 specification. Performance analysis shows that the EM1550 exhibits superior frequency domain characteristics when compared to previous NetComm microfilter models. The EM1550 will therefore deliver better filtering performance to end users with ADSL2+ to ensure little or no disruption to voice and data services