Methods and apparatus for providing data communication between modems
coupled over digital channels are provided. In one aspect, the present
invention features an apparatus used in a system for providing
communication over a digital channel to couple a first modem on a first
network to a second modem on a second network. The apparatus includes a
modem module that couples to the first modem at a data rate determined in
part by a modulation rate of the modem module. The apparatus further
includes a digital channel interface module coupled to the modem module,
the digital channel interface module including a buffer that receives data
from the digital channel and provides data to the modem module. The
apparatus also includes a control circuit that detects a level of data in
the buffer and modifies the modulation rate of the modem module based on
the level of data detected.