versa it should be further apparent that modems 502 and 504 can include additional components and functionality not shown in fig5 the following will further describe items related to the implementation of the above mentioned timing recovery framework 1 to maximize savings on power dissipation the formation of symbols carrying only pilot tones by symbol generator 514 may be implemented using a memory 506 ram or rom lookup technique in the upstream modem 502 where the dsp performing the normal transmit and receive function may be disabled a during initialization the upstream i e co modem 502 and downstream i e cpe modem 504 specify the maximum duration of a downstream inactivity interval in a tdd frame i e t inactive in a standard or interoperability specification for example during initialization the downstream receiver may specify the number of pilot symbols needed per tdd frame during periods of inactivity to maintain timing recovery the downstream receiver may also specify the bit loading in the downstream transmitter commensurate with the period of inactivity to assure error free transmission in the presence of extended timing drift b also during initialization the downstream modem 504 selects the number of pilot tones for the upstream modem 502 to include in a downstream data symbol as well as their indices and communicates.