Spectrum Compatibility means the capability of two (2) copper loop transmission system technologies to coexist in the same cable without service degradation and to operate satisfactorily in the presence of cross talk noise from each other. Spectrum compatibility is defined on a per twisted pair basis for specific well-defined transmission systems. For the purposes of issues regarding Spectrum Compatibility, service degradation means the failure to meet the Bit Error Ratio (BER) and Signal-to-Noise Ratio (SNR) margin requirements defined for the specific transmission system for all Loop lengths, model Loops, or loss values within the requirements for the specific transmission system.
SDSL or "Symmetric Digital Subscriber Line" is a baseband DSL transmission technology that permits the bi-directional transmission from up to 160 kbps to 2.048 Mbps on a single pair. "VDSL" or "Very High Speed Digital Subscriber Line" is a baseband DSL transmission technology that permits the transmission of up to 52 Mbps downstream (from the Central Office to the End User Customer) and up to 2.3 Mbps digital signal upstream (from the End User Customer to the Central Office). VDSL can also be 26 Mbps symmetrical, or other combination.