6. Ring back and Caller ID

Many times the number you are calling is engaged. Your option is to try and call again a bit later. This can be inconvenient and you may even forget to make the call at a later time.

To overcome this difficulty, the Ring back service was developed.

When you hear the engaged tone, the ring back service is activated by pressing a code on your phone. The ring back service will then detect when the line is free once more. As soon as it is free, your telephone rings in a certain way to let you know that you can now make the call. When you pick up the phone, the number is dialed and the call established.

Internal private telephone systems also include ring back so workers can call each other at their earliest convenience.

Caller ID

If you want to know the number of the caller, a service called 'caller ID' is offered. You dial a code such as 1471 and an automated messaging service speaks out the last telephone number received. This will not work if the person withheld their number, or called from a company switchboard or a payphone.