The Keysight 3421 (previously Agilent Technologies) is a self contained measurement system. A computer and (of course) your transducers are the only other devices required for data gathering and analysis.
The Keysight Model 3421A is a fully programmable unit combining precision measurement capability with process monitoring and control functions. When interfaced to an hp computer such as the HP-85) or handheld calculator the 3421A forms a versatile, easy to use data acquisition and control system.
Keysight 3421A Data Acquisition Control Units were previously manufactured by Agilent Technologies.