John Bickerton had a conflict between a Mac 5500/225 and CTX EzPro 500 LCD projector. CTX tech support offered the solution. John writes: "CTX knew all about the problem. They sent (no charge) a Mac adapter for the External Video Connector that has built in dip switches. It worked! CTX also said that PowerR makes their version of the External Video Connector which also solves the problem. CTX indicated that this incompatibility is also found in the 5400 series."