What is the prefix to make your number known to the other caller?

Our work phone comes up as an unknown number when we call clients (as intended). But sometimes we need to have our number come up. I know there is a way to prefix the telephone number dialed to make this happen, but I can't remember the prefix!

Anyone tell me what it is?

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia…).