When testing the setup of a Fritz!Box 7490 with fiber connection, routing anonymous/withheld ISDN calls to a new answering machine I needed to test if only Caller ID calls were getting through.
The easiest was to do this from my mobile phone.
Izzy explained how to in callerid – How can I make anonymous calls for everyone but contact list? – Android Enthusiasts Stack Exchange.
Basically all cellular networks based on GSM or derived technologies allow you to prefix any phone numbers with:
- #31# to disable caller ID
- *31# to enable caller ID
–jeroen
