Yes, Shimano gear cable. Campag's barrel is smaller.
There are some precautions you need to take. Use the correct allen key. IIRC it is 2mm. However, do NOT use a ball-end allen key. Grind the ball end off if that's all you have.
Then, turn the switch to open (fork can compress). Loosen the cable at the fork and pull it out at the lever. Replace.
Make sure the switch is on the open (not lock-out) position and wrap the cable around the wheel. Now with your other two hands, put a leeeeeetle bit of preload on the lockout and tighten the grub screw.
You have once chance at this because the screw just about destroys the cable. Test that when the switch is on, you cannot turn the lockout wheel on the fork any further. If you can, adjust it with the barrel adjuster. Did I mention that your barrel adjuster should be in the middle of its two limits before you fit the new cable?