How it works PGD ICSP pins on PIC24F?

[E_Blue]

I'm new on PIC24FJ and read that there's 3 pairs on PGC&PGD pins and seems like the default are PGC1 & PGD1
Now I wondering if I want to use one of the other pairs on a blank new device Should I first program them using PGC1 & PGD1 pair or I can directly use any of them?
If so, What's the purpose of those bits(ICS<1:0>)
_________________
Electric Blue

[newguy]

On a blank device any of the ICSP pairs may be used to program the device. When you program it, you can select a particular ICSPn fuse corresponding to the ICSP "port" you're using. Once that is done, only that port may be used to program the part until the fuses are reset/erased.

[E_Blue]

Ok, thanks for your answer.
_________________
Electric Blue

[Ttelmah]

In fact you can always _program_ on any pair of the pins.
The fuses have to be set to enable debugging on the pins.
So
#DEVICE ICSP=2

for example tells the compiler to set the fuses to use the PGC2/PGD2 pins
for debugging.

From the reference manual: