PIP stands for Programmable Input Processor. These are optional modules that can be plugged into any PIP-compatible amplifier . There are a variety of PIP modules with varying functions. Since first introducing PIP-compatible amplifiers and PIP modules, Crown has updated the PIP standard. This affects which PIP-compatible amplifiers can host certain PIP modules. For more information on the differences between the original PIP and PIP2 standards, click here.