Depending on the vintage of amplifier and type of PIP, there are some combinations that work better together than others. The most important issue is PIP versus PIP2. The IQ-PIP-USP2 and IQ-PIP-USP2/CN may only be installed in a PIP2 amplifier. The IQ-P.I.P.-MEM and IQ-P.I.P.-SMT will function in either a PIP or a PIP2 amplifier. From a strictly IQ perspective, all of these modules communicate using our newer IQ2 protocol. An IQ-INT III or IQ-USM 810 is required as the system interface (older mixers cannot be used).