A method of sending data in a multiple antenna system according to an aspect of the present invention includes performing precoding on received symbols based on a second codebook generated from a first codebook for a plurality of transmission antennas and sending the precoded symbols. The use of such a method or system in an Ethernet network can result in a reduction in the number of flooded multicast messages. The SIP call processor selects per-trunk-group call processing data based on the incoming SIP trunk group. In one embodiment the control unit receives a reset signal and performs a calibration routine in response.