AudioCodes Mediant 800B - Page 505

Version 7.2 505 Mediant 800B Gateway & E-SBC
User's Manual 22. Digital PSTN
Once a SIP-based private wire is established, the private wire user may wish to signal any
of the following private wire events to the far-end private wire user, at any time during the
"always-on" call:

Hook Switch (On Hook and Off Hook states): This event signals a change in the
state of an electronic hook switch. An example is when the user connects a wireless
headset to the phone.

Ring Down (Ring and No Ring states): This event signals a ring or no ring state. An
example is when the user lifts the handset or pushes a button on the phone to alert
the far-end user, which instantly sends ringing to the far end (even though they are
already connected). This is also known as Automatic Ring Down (ARD) or Manual
Ring Down (MRD).

TOS (transmission only service): If neither Ring Down or Hook Switch modes are
specified in the INVITE, TOS is assumed. In this case, the device ignores all CAS
signaling, replies with 200 OK and opens a media channel.
These special private wire events are signaled during a call using the SIP INFO message
in association with the INFO package (per IETF draft). The INFO package is the INFO
message's body, which is in XML schema. The root element of the XML is "<pwsignal>",
which contains two child elements:

"<ringDown>" - requests a local Ring Down alert

"<hookSwitch>" - requests a Hook Switch alert:
♦ "onHook" - signals that the endpoint is not in use
♦ "offHook" - signals that the endpoint is in use
The following is an example of the XML for private wire signaling in the SIP INFO
message:
<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema targetNamespace="urn:bt-trs:params:xml:ns:private-
wire:0"
xmlns="urn:bt-trs:params:xml:ns:private-wire:0"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
elementFormDefault="qualified"
version="0.1">
<xsd:annotation>
<xsd:documentation xml:lang="en">Version 0.1 Draft XML
schema
for Private Wire Signalling in SIP INFO body
</xsd:documentation>
</xsd:annotation>
<!-- pwSignal -->
<xsd:complexType name="pwSignallingType">
<xsd:sequence>
<xsd:choice>
<xsd:element ref="ringDown" />
<xsd:element ref="hookSwitch" />
<xsd:any namespace="##other" minOccurs="0"
maxOccurs="unbounded" processContents="lax" />
</xsd:choice>
</xsd:sequence>
<xsd:anyAttribute namespace="##other" processContents="lax" />
</xsd:complexType>
<xsd:element name="pwSignal" type="pwSignallingType"/>
<!-- ringDown -->
<xsd:complexType name="ringDownType">
<xsd:sequence>
<xsd:any namespace="##other" minOccurs="0"