Mobile PBX is a service that provides customary PBX features but allows the use of mobile phones instead of IP phones.
When end users answer calls on their mobile phones, they must have the capacity to distinguish direct incoming calls from calls received via hunt groups/call queues so that they answer them differently.
For example, one may answer a call received via a hunt group/call queue with, "Good morning! EasyCall sales, John Doe speaking. How may I help you?" But if a colleague dials directly to an extension, the script might be, "Sales, John Doe speaking."
An administrator configures dialing rules that modify CLIs for calls that are passing through a hunt group/call queue as follows: 00<CLI>. PortaBilling sends modified CLIs to the mobile core. When end users see 00, they understand that a call comes via a hunt group or a call queue while direct calls are displayed as +<CLI>.
For example, to modify CLIs for calls received via hunt group 111, the administrator defines the dialing rules as follows:
($TR{via_hg} =~ /^111/ and s/^/00/) or (s/^/+/);
In this expression, $TR{via_hg} =~ /^111/ checks whether a call is received via hunt group 111. If this condition is met, the CLI is modified as 00<CLI>, otherwise, as +<CLI>.
This allows Mobile PBX users to see whether calls are either direct or routed from a hunt group/call queue and treat those calls accordingly.