Caller ID block allows the users phone number not to appear to the person they call. Anonymous call block prevents calls with unknown caller ID from ringing the IP phone. If the caller has set the phone to block caller ID, then the caller hears a busy signal or message when anonymous call blocking feature is enabled.
This document explains some possible options to block caller ID and anonymous calls on Cisco SPA300 series IP Phones.
Depending on the model and Firmware version, SPA Phones may service from an Internet Telephony Service Provider (ITSP) or an IP Private Branch Exchange (PBX) call control server. WebEx Calling, Ring Central, and Verizon are examples of an ITSP. Some examples of IP PBX services that may work with SPA phones include, Asterisk, Centile, and Metaswitch platforms.
These ITSP and IP PBX call controllers are a separate system in which the phone and the call controller communicate with each other to provide services such as call park, voicemail, and caller ID. Since SPA phones do not use a specific call controller, access and procedures vary.
Each call controller can follow different procedures, so we can't tell you exactly how yours will work. For information and help with your specific commands, refer to the help sites from the provider you chose. If you have an administrator, contact them for details and possible training.
That being said, depending on how your SPA phones have been configured, these codes may or may not work for you.
Step 1. Dial *67 followed by the phone number to block the caller ID.
Step 2. Dial *68 followed by the phone number to disable caller ID blocking.
Note: Caller ID block remains enabled for all calls until the user enters *68.
Step 1. To activate anonymous call block, enter *77.
Step 2. To deactivate anonymous call block, enter *87.
Note: Anonymous call block remains enabled until the user enters *87.
Another option is to try to enable through the GUI
For assistance in logging into the GUI of an IP phone, click here.
To enable Anonymous Call and Caller ID Blocking navigate to Admin Login > advanced > Voice > User. Under Supplementary Services under the type of call blocking, choose yes to enable or no to disable:
For more information on the SPA300 Series IP Phones, check out the SPA300 Product Page that provides links to other SPA300 documentation.