Frequently Asked Questions (FAQs):System Overview

VoIP: System Overview

Inbound Calls

Inbound calls from all suppliers should come to sip.freevirtualnumbers.co.uk.

Specifically, the inbound call will be of the format: CCAAAANNNNNN@sip.freevirtualnumbers.co.uk where CC is the country code, AAAA the area code, and NNNNNN the number, e.g. 448717502474@sip.freevirtualnumbers.co.uk. The SER process on sip then does one of the following:

  • If the number is a pure SIP forward, the call is routed to the specified destination, regardless of customer type.
  • If the number belongs to a PBX customer, the call is routed to CCAAAANNNNNN@lon-pbx-N.freevirtualnumbers.co.uk.
  • If the number belongs to a regular single line customer, the call is delivered to their extension (with optional voicemail and divert processing described later).

Outbound Calls

Outbound calls are sent to sip.freevirtualnumbers.co.uk in UK dialled format at present, i.e. 08717502474@sip.freevirtualnumbers.co.uk for UK calls or 00CCAAAANNNNNN@sip.freevirtualnumbers.co.uk for all other international calls.

The call is then forwarded appropriately to a SIP termination supplier.

Outbound calls are passed to sip from either lon-pbx-1 or the other Centrex servers that are in operation