Pause a print

i started experimenting multicolour prints with my taz4 with one extruder. Is it possible to pause and resume automatically a print with slic3r, any other slicing software or G-code sending applications?

Read through this thread for some tips:

Here a the code I have some up to with. Should work with most print servers or if you have an LCD. Includes homing XY in chase of accidental moments while changing filament

            ;Pause Code
G91            ;Set Relative Mode
G1 E-5.000000 F500   ;Retract 5mm
G1 Z15 F300         ;move Z up 15mm
G90            ;Set Absolute Mode
G1 X20 Y20 F9000      ;Move to hold position
G91            ;Set Relative Mode
G1 E-40 F500      ;Retract 40mm
M0            ;Idle Hold
G90            ;Set Absolute Mode
G1 F5000         ;Set speed limits
G28 X0 Y0         ;Home X Y
M82            ;Set extruder to Absolute Mode
G92 E0         ;Set Extruder to 0

In what position of the file should I add the cose? Does it pause the print, let me change the printer, and have the print resume when I resume it? (how?)

You can insert this after the last layer of one color. It can be added in multiple locations in the gcode for multie color changes

To insert the code at the exact point I whato (ie at the middle of the printing process), there is a way to know exactly where is it?

You will have to use your slicer to visualize the gcode. Insert the code after the last layer of old color, before first layer you want to be new color. Most slicers will insert a comment i.e. ;layer xx at each layer change.