There are two ways to ensure, via our SIP Trunk Plus portal, that the outbound number CLI (calling line identification) is witheld.
(a) Permant 'Privacy' / Number Witheld (per DDI)...
1. Via the 'Numbers' tab, right click on a DDI (one that is already assigned to a trunk) end select 'Edit'.
Any outbound calls from the attempting to present the DDI will be supressed from doing so. Do note that other DDI's will still present their CLI unless they too have thier 'Privacy' option set.
(b) Ad-hoc 'Privacy' / Number Witheld (per call)...
1. If a caller prefixes the number they are dialling with feature / star code *20 this will force withholding of the CLI presentation.
2. Similarly prefixing *21 will force presenting the DDI as the CLI. Note that *21 overrides (a) above.
Please note that your PBX's feature / star codes may need reviewing as *20 and *21 may already be PBX-based star codes. Similarly the PBX's outbound routing policies will also need to be reviewed and potentially amended to allow outbound calls to be prefixed with *20 and *21.