AudioCodes Mediant 500 E-SBC, User Manual

Page: 436 / 920

User's Manual 436 Document #: LTRT-10437
Mediant 500 E-SBC
26.7 Detecting Collect Calls
The device detects collect calls (reverse charge calls) using any of the following
information elements (IE) in the received Q.931 ISDN Setup message for Tel-to-IP calls:

Reverse Charging Indication IE

Facility IE
When the device detects a collect call, it adds a proprietary header (X-Siemens-Call-Type:
collect call) to the outgoing SIP INVITE message.
This support does not require any configuration and is applicable to the Euro ISDN protocol
variant.
26.8 Advice of Charge Services for Euro ISDN
Advice of charge (AOC) is a pre-billing function that tasks the rating engine with calculating
the cost of using a service and relaying that information back to the customer (caller). This
allows users to obtain call charging information periodically - during the call (AOC-D) and at
the end of the call (AOC-E).
The AOC messages are sent in the EURO ISDN Facility Information Element (IE)
message. The device interworks these ISDN messages with SIP by converting the AOC
messages into SIP INFO (during call) and BYE messages (end of call), using AudioCodes
proprietary SIP AOC header, and vice versa. The device supports both currency (monetary
units) and pulse (non-monetary units) AOC messages.
This feature can typically be implemented in the hotel industry, where external calls made
by guests can be billed accurately. In such a setup, the device is connected on one side to
a PBX through an ISDN line (Euro ISDN), and on the other side to a SIP trunk provided by
an ITSP. When a call is made by a guest, the device first sends an AOC-D Facility
message to the PBX indicating the connection charge unit, and then sends subsequent
AOC-D messages every user-defined interval to indicate the charge unit during the call.
When the call ends, the device sends an AOC-E Facility message to the PBX indicating the
total number of charged units.
The device supports various methods for AOC:

Tel-to-IP direction: The device converts the AOC messages received in the EURO
ISDN Facility IE messages into SIP INFO and BYE messages using AudioCodes
proprietary SIP AOC header.

IP-to-Tel direction provides optional methods:
•
The device generates the metering tones according to user-defined pulses and
intervals, configured in the Charge Code table (see ''Configuring Charge Codes''
on page
438 ). These include:
♦
'Pulses On Answer' - number of charging units in the first generated AOC-D
Facility message.
♦
'Pulse Interval' - time between every sent AOC-D Facility message.
♦
'End Time' - time at which the charge code ends.
•
TELES proprietary method. For more information, see the
PayPhoneMeteringMode parameter in Metering Tone Parameters on page
861 .
•
Cirpack proprietary methods. For more information, see the
PayPhoneMeteringMode parameter.