An downstream external Physical Layer (PHY) interface between a network and an edge quadrature amplitude modulator (EQAM) is provided. The interface comprises, an input direct memory access (DMA) controller enabled to control rate of packets received from the network, a plurality of buffers to store received packets, a first module enabled to convert packets to a first format and a second module enabled to convert packets to a second format. The interface further comprises a plurality of processors enabled to customize an output format of packets based on instructions stored in an instruction memory and a plurality of flow meters enabled to determine an output rate for packets based on, at least in part, a modulator rate of the EQAM. An output DMA controller controls the rate of egress of packets to the EQAM.