SMB 120 SMB female to BNC female (jack) connectors 10 dB Attenuation built into cable 600 mm length Overview The SMB-120 is designed to be used with the NI 4472 and 4474 DSA devices. With 10 dB of attenuation built into the cable, the SMB-120 extends the measurement range of the 447x device from +/- 10 V to +/- 31.6 V. The SMB-120 is ideal for connecting proximity probes, keyphasors, and other eddy current probes to the NI 4472 and 4474.