Vendors that provide toll-free numbers to service providers can charge a different price for calls that originate from a payphone or a paystation.

With PortaSwitch, service providers can take call origination into account when charging their customers and calculating calls’ cost on the incoming connections (Calls from Vendor via SIP and Calls from Vendor via PSTN).

Call origination type is determined based on the Origination Line Information (OLI) parameter. The OLI is transmitted over PSTN networks as signals. There is no common standard for carrying OLI over SIP, but one popular way is to use the isup-oli SIP URI parameter and include it in the SIP INVITE message, notably in the From header.

For example, for calls made from a payphone, the From header may look like the following:

From: "18005551155" <sip:18005551155@;isup-oli=27>;tag=gK037dd60b

PortaSIP extracts this value and assigns it to the Originating-Line-Info RADIUS attribute which will be then passed to PortaBilling:

NAS-IP-Address = ''
‎User-Name = '18005551155'


Originating-Line-Info = '27'


Using this value, the billing engine seeks a rating entry that can match it, and if one is found, it both charges for the call and calculates the call cost accordingly.

OLI (Info Digits)

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OLI digit pairs and their descriptions are represented in the following table:

Value Description
0 pots
1 multiparty line
2 ANI failure
6 Station Level Rating
7 special operator handling required
8 inter-LATA restricted
10 test call
20 AIOD-listed DN sent
23 coin or non coin on calls using database access
24 800 service call
25 800 service call from a pay station
27 payphone using coin control signaling
29 prison or inmate service
30 intercept (blank)
31 intercept (trouble)
32 intercept (regular)
34 telco operator handled call
36 CPE
60 TRS call from unrestricted line
61 wireless or cellular PCS (type 1)
62 wireless or cellular PCS (type 2)
63 wireless or cellular PCS (roaming)
66 TRS call frm restricted line
67 TRS call from restricted line
68 inter-LATA restricted hotel
70 private paystations
78 inter-LATA restricted coinless
93 private virtual network

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