Cable Modem Interface

Varis’ Cable Modem Interface Unit (RNG-CMI) provides an interface between the Smart Com Leaky Feeder network and cable modem hardware. The CMTSI and RNG-CMI units work together to compensate for the Varis Smart Com network not having the same upstream band-pass as CATV networks. The interface units perform a frequency translation to insert and extract a 6.4 MHz wide 64 QAM data channel. The RNG-CMI performs an up-conversion from CATV sub-band upstream frequencies to Smart Com VHF upstream frequencies, while the CMTSI does the opposite. In addition to performing upstream frequency conversion, the RNG-CMI also accommodates the downstream channel and performs power level adjustments for both channels.