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*prefix 5 phone number#
If you phone number is 0871234567:
Key in *21*08751234567#

2b - Divert missed calls

To select for how long you want your phone to ring before the call is diverted:
Key in **61*prefix 5 phone number**the required number of seconds#
If you phone number is 0871234567:
Key in *61*08751234567**10#

2c - Divert if unavailable

Key in **62*prefix 5 phone number#
If you phone number is 0871234567:
Key in *62*08751234567#

2d - Divert if busy

Key in **67*prefix 5 phone number#
If you phone number is 0871234567:
Key in *67*08751234567#

Send request

Press Call.