In this case, the spoofing allowed the sending modem to continue sending packets as fast as it could. At the same time, the modem on the remote receiving end dropped the ACK packets being generated by the local computer's software, keeping the backchannel clear. Since the channel efficiency only became a major problem at speeds over 2400 bit/s, and modems able to run faster than that typically had significant processing power anyway, protocol spoofing was mostly associated with these higher-speed systems.