"Michael Black" wrote in message Generally, 6
pin DIPs are optoisolators.

There must be exceptions, but every time I see one I start
with the assumption that it's an optoisolator.

I vaguely remember Motorola's odd, short-lived
line of linear devices back in the 60s or 70s..
MFCxxx rings a bell. They had attenuators, oddball
audio amps. I think there were some six pin devices,
but they were also an offset lead package.

Pete