HP 59306A "Relay Actuator" (1973)
(click images to enlarge)
HP 59307A VHF Switch
HP 59501A Isolated Power Supply Programmer
The series 59xxx, introduced in 1973/74, were some of Hewlett-Packard's earliest dedicated peripherals
for the HP Interface Bus (HP-IB, GPIB, IEEE-488)
they had introduced around the same time.
The most intersting aspect of these devices is that they were constructed without the use of microprocessors (even the lowly Intel 8048 would only be introduced in 1976), they were built entirely from SSI TTL ICs.
Remarkably, most of these devices remained in HP's catalogues until the early 1990s.
The model 59306 contains six SPDT relays that can be operated through front panel pushbuttons or over the bus.
The 59307 VHF switch is similar to the 59306 but offers two 4-throw switches with BNC connectors, specified to 500 MHz.
The 59501 contains a 12-bit digital/analog converter. It was intended to provide an HPIB interface for power supplies with analog remote control terminals, but it can also be used as a stand-alone unit.