User`s manual

SIP User's Manual 8. Telephony Capabilities
Version 5.0 229 December 2006
8.4.2.4 FXO Supplementary Services
 Hold / Transfer toward the Tel side
The ini file parameter LineTransferMode must be set to 0 (default).
If the FXO receives a hook-flash from the IP side (using out-of-band or RFC 2833), the
gateway sends the hook-flash to the Tel side by one of the following:
• Performing a hook flash (i.e., on-hook and off-hook)
• Sending a hook-flash code (defined by the ini file parameter HookFlashCode)
The PBX may generate a dial tone that is sent to the IP, and the IP side may dial digits
of a new destination.
 Blind Transfer to the Tel side
A blind transfer is one in which the transferring phone connects the caller to a
destination line before ringback begins. The ini file parameter LineTransferMode must
be set to 1.
The blind transfer call process is as follows:
• FXO receives a REFER request from the IP side
• FXO sends a hook-flash to the PBX, dials the digits (that are received in the
Refer-To header), and then drops the line (on-hook). Note that the time between
flash to dial is according to the WaitForDialTime parameter.
• PBX performs the transfer internally
 Hold / Transfer toward the IP side
The FXO gateway doesn't initiate hold / transfer as a response to input from the Tel
side. If the FXO receives a REFER request (with or without replaces), it generates a
new INVITE according to the Refer-To header.
8.5 ThroughPacket™
The gateway supports a proprietary method to aggregate RTP streams from several
channels to reduce the bandwidth overhead caused by the attached Ethernet, IP, UDP and
RTP headers, and to reduce the packet / data transmission rate. This option reduces the
load on network routers and can typically save 50% (e.g., for G.723) on IP bandwidth.
ThroughPacket™ is accomplished by aggregating payloads from several channels that are
sent to the same destination IP address into a single IP packet.
ThroughPacket™ can be applied to the entire gateway or, using IP Profile, to specific IP
destinations (refer to Section 5.5.6.3 on page 113). Note that ThroughPacket™ must be
enabled on both gateways.
To enable ThroughPacket™ set the parameter ‘RemoteBaseUDPPort’ to a nonzero value.
Note that the value of ‘RemoteBaseUDPPort’ on the local gateway must equal the value of
‘BaseUDPPort’ of the remote gateway. The gateway uses these parameters to identify and
distribute the payloads from the received multiplexed IP packet to the relevant channels.
In ThroughPacket™ mode, the gateway uses a single UDP port for all incoming
multiplexed packets and a different port for outgoing packets. These ports are configured
using the parameters ‘L1L1ComplexTxUDPPort’ and ‘L1L1ComplexRxUDPPort’.
When ThroughPacket™ is used, Call statistics aren’t available (since there is no RTCP
flow).