VoIP
Aspire Software Manual Features 695

RTP Forwarding Available

With software 4.93+ the delay of the RTP packet is improved. Previously, the VOIPU PCB decoded
the RTP packet to voice. The voice returned to the VOIPU PCB through the backplane of the
Aspire. The VOIPU PCB would then encode the voice to the RTP packet to send it back out.
With RTP Forwarding now the VOIPU PCB does not decode the RTP packet, but instead just trans-
fers it. This decreases the delay necessary previously when the RTP packets were decoded.
This feature is supported with the following VOIPU PCB rmware:
VOIPU-A1 - rmware 4.5 or later
VOIPU-S1 - rmware 4.5 or later
VOIPU-B2 - rmware 4.3 or later
RTP Forwarding will take affect when:
Program 10-26-02 is enabled.
IP call via VOIPU P CB.
DSP channels on the same VOIPU PCB are used.
The codec and payload size used RTP packet 1 and RTP packet 2 are the same.
VAD mode is disabled.
Conditions
RTP Forwarding does not work with RFC2833 DTMF relay.
If a digit key on an IP phone is pressed, the RTP Forwarding is temporarily disabled. After a 5
second delay (Program 21-01-03 : Trunk Interdigit Timer), RTP Forwarding is automatically
enabled.
If RTP Forwarding is enabled and RTP packets are not sent from the other phone, an error
tone is heard.
If IP phones use G.723 codec, RTP Forwarding does not work between the IP phone and
another terminal/trunk.
Programming
10-26-02 : IP System Operation Setup - RTP Forwarding
Enable (1) or disable (0) RTP Forwarding for the system. If this option is disabled, the DSP is
used from the VOIPU which low load channel. If this option is enabled, the DSP is used from
the same VOIPU channel.

Tandem Connection

To call from one Aspire system to another, set the following programs.
Programming
15-05-12 : IP Phone Terminal Basic Data Setup - System Type
Dene whether or not the Aspire system is interconnected (0=no system, 1=Second Aspire
system).
15-05-13 : IP Phone Terminal Basic Data Setup - IP Address for Other System
Dene the IP address for the connected system.
15-05-14 : IP Phone Terminal Basic Data Setup - Call Control Port for Other System
The Call Control Port for the other system is dened in this program. This item is xed at
1720 and it cannot be changed.