iPhone Call Forward PropertiesFor some strange reason, the call diversion features on the Apple iPhone are a bit lacking.

On Android, you’re able to easily set diversions based on “No answer”, “Busy” & “Not contactable”.

On the iPhone, the options aren’t there.  So you need to set the diversions the old fashioned way.  Using the GSM Feature Codes.

Function Dial
Divert all  
Activate divert all **21*<voicemail>#
Deactivate divert all ##21#
Query divert all *#21#
   
Divert on no answer  
Activate divert when no answer **61*<voicemail>#
Activate divert when no answer after X seconds **61*<voicemail>**<xx>#
Deactivate divert when no answer ##61#
Query divert when no answer *#61#
   
Divert when not reachable  
Activate divert when not reachable **62*<voicemail>#
Deactivate divert when not reachable ##62#
Query divert when not reachable *#62#
   
Divert when busy  
Activate divert when busy **67*<voicemail>#
Deactivate divert when busy ##67#
Query divert when busy *#67#

 

And for completeness, some other GSM Feature codes.

Function Dial
Own number *#100*
(Telstra network: a menu is displayed)
HLR number *#101#
(Telstra network: Messagebank calls you)
Switch number *#102# or *#105#
Network time *#103#
Voice mailbox number *#104#
Last call *#147#