Hi -

I'm building a cable tester for 8 wire UTP, cat III - V (normal 10Mb/s
network cables) up to 100m.
Using a 16F84 I am wondering if I should use any ESD prevention.

My setup looks something like this: (plz. use a Courier font)

----+      -- +5V                  -- +5V  +---
16F +      +                       +       +16F
84  +    Diode                   Diode     +84
    +      +                       +       +
RBx +--1K--------Twisted cable-----+---1K--+Rbx
    +      +                       +       +
    +    Diode                   Diode     +
----+      +                       +       +---
           -- GND                  --GND

The 1K resistors are not for ESD, but I may "short-circuit" 2 or more pins.
My question is: Are the diodes needed?
I have read (page 23, note 2 in Microchips F84 manual) that
"I/O pins have diode protection to VDD and VSS".
But can I trust that? Are they strong enough for an ESD discharge?

/holger
hmo@q8.dk