ATT phone codes

via: http://scottcate.com/blog/voicemail-codes-to-remember-for-att-phone-users/

Codes for forwarding calls to your ATT phone to another destination number based on the status of your cell phone.

*004* is a command that is used to set Forwarding, Busy, and No Answer, all at once.

*004*1[Destination Phone Number]*11# (Then press Talk or Send)

Individual Settings based on Phone Status

Forward All Calls command prefix: *21*
Activate: *21*1[Destination Phone Number]*11# (Then press Talk or Send)
Cancel & Retain: *21*11# (Then press Talk or Send) this option remembers the number, but disables forwarding
Re-establish: *21*11# (Then press Talk or Send) this option engages forwarding to the last number (notice this is just a toggle command
Cancel & Forget: ##21*11# (Then press Talk or Send) Disable forwarding, and forget the last number used to forward
Status: *#21*11# (Then press Talk or Send) this sends you back status of your forwarding number

Forward If Busy:
Activate: *67*1[Destination Phone Number]*11#
Cancel & Retain: #67*11#
Re-establish: *67*11#
Cancel & Forget: ##67*11#
Status: *#67*11#

Forward if no answer: Ring for 15 (see the 15 at the end of the activate command) seconds, and then forwards to destination number.
Activate: *61*1[Destination Phone Number]*11*15#
Cancel & Retain: #61*11#
Re-establish: *61*11#
Cancel & Forget: ##61*11#
Status: *#61*11#

Forward If Unreachable: (When you phone is off, or out of a service area)
Activate: *62*1[Destination Phone Number]*11#
Cancel & Retain: #62*11#
Re-establish: *62*11#
Cancel & Forget: ##62*11#
Status: *#62*11#