Just to keep flogging a dead horse...

>>RS-232 Drivers is insufficient to put the chip into programming mode).
>
>No, there's plenty of power there for a desktop box to do it.

Uhmmm...  Are you sure?  I just looked at the RS-232 voltage levels at the
12C509 GP3 pin on a scope, the Negative Voltage through the 10K Resistor and
Clamping diode is 0.2 Volts and the Positive is 10 Volts.

Looking at the data sheet, to put the part into Programming Mode voltage
input is 12.75 - 13.24 Volts.  Now, there is a verify specification of Vdd +
4.0 Volts (which this set up would seem to put the PIC Into).

The Programming Supply current is only specified as a maximum (which is 50
mA for both the 12C5xx parts and the 16Cxx EPROM parts).  I seem to remember
that it is normally 3+ mA (which, the Serial Port will NOT be able to supply
with the 10K Resistor and still maintain the programming voltages).

Maybe somebody from Microchip (or anybody that knows better) can confirm
what I'm saying here and state whether or not there's any danger of me
putting the device into programming mode.

myke

"I was well aware that the processes of puberty are often fatal to psychic
power."
- Sir Arthur Conan Doyle