The Input Menu shows the analog input channels currently available in your analyzer. Please contact Norsonic if you are missing some possibilities.
A fully equipped Nor150 has:
Two sound input channels for microphones and preamplifiers called Sound 1 and Sound 2 (Or for short S1 and S2).
The sockets for S2 is locaated behind the rubber lid on the left hand side of the instrument.

The sound input channels can take both traditional (Lemo style) preamplifiers and microphones and prepolarized microphones on IEPE preamplifiers. When using the Lemo style preamplifier, the microphones can either be with or without polarization voltage (pre-polarized).