Over the years people have asked us to describe the differences between the Model 41 Interface and the Model 42A Interface. The answer is simple: Both units unit have the same circuitry, perform the same functions, and have four 3-pin male XLR connectors on their back panel for access to the powered IFB outputs. But the Model 42A also has four 3-pin male XLR connectors on its front panel. This can be useful when you need direct, front-panel access to the IFB outputs for “booth kit” or portable rack applications. For details please see:
https://studio-tech.com/wp-content/uploads/2018/06/cs_4142a_1.pdf .