Pin 6 doesn't connect to anything on a DB9. I have a PIC16F84 talking with my HP7475a -- you just need TxD, RxD, Signal Ground and CTS hooked up (well, you don't even need RxD hooked up since the HP7475a is just receiving.) For those of you who are interested, I just have a MAX232, pin 2 (+ 10V from the charge pump) to assert a "SPACE" to pin 4 of the DB9.
Message
Re: hp7470a:wirring interface problem
2002-07-19 by caveteursus