Apple iPhone 4

Find "Phone"

Press Phone.

Choose option

Choose one of the following options:
Divert all calls, go to 2a.
Divert missed calls, go to 2b.
Divert if unavailable, go to 2c.
Divert if busy, go to 2d.

2a - Divert all calls

Key in **21*+61414121121#

2b - Divert missed calls

To select for how long you want your phone to ring before the call is diverted:
Key in **61*+61414121121**the required number of seconds#
Eg:
*61*+61414121121**5#

2c - Divert if unavailable

Key in**62*+61414121121#

2d - Divert if busy

Key in**67*+61414121121#

Send request

Press Call.