Long ago I setup Google Voice as my son’s phone’s voicemail using “conditional call forwarding” on H2O Wireless mobile (very cheap, but also weak IT service). I switched him from H2O Wireless to our family AT&T account and wanted to disable the forwarding.
Unfortunately I couldn’t get Google Voice legacy site to come up on my iPhone so I didn’t disable Conditional Call Forwarding prior to the port. I tried removing the his number from GV but that doesn’t work — it only messes up Google Voice (below).
After the port I couldn’t set a voice mail code for his account. It seemed like voice mail was setup, but when I called him I was routed to Google Voice. Alas, there’s no useful error message.
I restored his mobile number as a forwarding phone in Google Voice but there was no option for him in Legacy Google Voice to add or remove conditional call forwarding, no “Activate Google voicemail on this phone”. (Probably because the call forward was already in place.)
I tried a #21# trick I read of, but that didn’t work. I thought I’d have to call AT&T but after several searches I found an obscure site with the answer: Dial #61#. That clears “call forward if not answered”. I also used the other deactivation codes as below (67, 61, 62).
I don’t know if that site will stay around, and I couldn’t find this information anywhere else, so here are the set of deactivate codes for several purposes:
To deactivate “Call forward if busy”,
Simply dial #67# and tap “Call”
To deactivate “Call forward if not answered”,
Simply dial #61# and tap “Call”
To deactivate “Call forward if not reachable”,
Simply dial #62# and tap “Call”
Android phones may have more control over Call Forwarding but iOS has only forward or don’t forward.
The site also reviews how to setup call forwarding, for example:
To setup “Call forward if busy”,
simply dial
*67*{NumberRetrieved}*11# and tap “Call”
After using those codes I could set a PIN for his voicemail and it worked normally.