There are a number of different service available, depending on which type of calling system you are using. Here is a brief rundown of each:

Security and privacy

Most teleconferencing services offer a degree of privacy and security. To do this, you have to enter a secure calling number along with a password to enter the teleconference. This way, you can keep unwanted guests out of your conference call.

Toll-free dial in numbers

As long as you're dialing a toll free number when you dial into your conference call, you'll never pay a service fee. Toll-free call in numbers are important so you don't get stuck with a large bill for the conference later.

Computer call-in or phone call-in

Some services do not require you to have a computer. This can be excellent as in most corporate settings, there are not always computers in the conference room.