| Keyword | Most frequent expressions (number of websites) |
|---|---|
| pbx | voip pbx (3), pbx system (3), pbx open (2), asterisk pbx (2), telecom pbx (1), corporate pbx (1), pbx forward (1), pbx platform (1), ff pbx (1), pbx demo (1), access pbx (1), cloud pbx (1), pbx configuration (1) |