Whether it’s because you’re unsure about a number from a call you’re returning, or for more personal security purposes, having your number flash up on the display of the person you’re calling isn’t always the best strategy.
The methodology for doing so is the same across all networks if you just need it on an ad-hoc basis.
If you’re dialling from a fixed line phone, adding 1831 before the number will make your call come up as a private call with no caller ID attached.
If you’re dialling from a mobile, then add #31# followed by the number you want to call.
Eg.: #31#012345678 and CALL
It’s also feasible to do this from within most phone settings, because that controls the sending of caller ID.
On iPhones, it’s found under Settings>Phone>Show My Caller ID
On Android devices it should be found by going into the menu from the phone dialler, choosing additional settings and then caller ID
On Windows Phone 8 devices, go to the dialler, choose the ellipses, then settings, then “Show My Caller ID”
On Blackberry devices, swipe down in the phone dialler and choose the cog icon. The default option is “Show my number”. Tapping on that should bring up “Allow My Number to Appear” which you can then switch to off.