HP (Hewlett-Packard) HP 85660B ユーザーズマニュアル

Each flag can be enabled (interrogated), or all flags can be enabled. 

 and U32 provide the

logic, and 

 stores the state of the enabled flags.

U7, 

 and U33 decode the address lines, enabling the appropriate 

 to gate or store data

for the Data Bus.

U8 is a PROM (programmable read-only memory) that contains the attenuation errors
(calibration data) of the RF attenuator.

 controls certain mainframe functions, such as turning off the internal reference oscillator

(IISTD).

 gates the Options jumpers onto the Data Bus.

2   A 1 2