Introduced in 1983; see HP Journal of February 1983.
The 3478A multimeter is a low-cost HP-IB (IEEE 488) programmable instrument for system measurements. A compan ion product to the 3468A with similar display and measurement features, the microprocessor-based 3478A is an autoranging, 5 1/2-to-3 1/2-digit, five-function digital multimeter […]
This model also has a lot in common with the 3457A (similar calibration data, LCD protocol, etc).
The 3478A contains one main CPU (Intel i8039) and one CPU in the analog domain (i8049).