PCID4ZP is a type of SelSync (Selsync Professional for Multi-Channel Processors) digital signal processor (DSP) module designed by Crystal Semiconductor Corporation. It is a four-channel, full-featured multi-channel processor (MCP) device featuring four-channel stereo analog to digital data conversion and two-channel digital to analog data conversion. The four-channel analog inputs, two of which are balanced analog inputs, provide the ability to process four independent channels of audio. The two-channel digital outputs allow for the connection of one or two external digital audio devices. The PCID4ZP includes 32-bit operation frequency at up to 48kHz, four programmable equalizers, four configurable compressor/limiters, four advanced digital peak limiters, four low-latency delay processors, and full multi-channel mixing capabilities.