Citel 6000 Guía Del Usuario
PBXgateway
™
& EXTender
TM
6000 System Administrator’s Guide
63
Setting Voice Parameters (Gateway Only)
Introduction
The MI provides a menu for setting voice parameters for each phone port for
the PBXgateway. The following parameters are covered:
Method (of compression)-Selectable voice compression methods reduce
network bandwidth requirements. (refer to Appendix B for more information on
Bandwidth Settings)
Path – This will set the voice path to Dynamic or Constant. Dynamic means
that the Branch Office unit uses the available bandwidth when the remote user
goes off-hook. Constant means that the voice path is always reserved.
DTMF (Avaya Only) – The method of sending tones, which correspond to
numbers, pressed on the telephone, across the network. The tones can be
sent as voice (In-band), or as signals (Out-of-band).
Attenuation– Attenuation decreases the signal being sent to the PBX. This
can be adjusted to decrease the amount of echo during calls.
Silence Detection - When enabled, the Extender detects silent periods during
a conversation, and as a result sends no data during these periods. This
dramatically reduces bandwidth usage, so this parameter should be Enabled
(default setting).
Jitter-The amount of delay (in msec) in sending voice packets. Used to
accommodate jitter (or variable delay) in an IP network. If not set properly
voice may sound choppy.
Packet Size-The number of voice windows included within HDLC on an IP
Packet. It generally reduces packet loss and bandwidth needs, but it will cause
some additional delay in voice delivery.
Packet Trace-Used for debug purposes only.
the PBXgateway. The following parameters are covered:
Method (of compression)-Selectable voice compression methods reduce
network bandwidth requirements. (refer to Appendix B for more information on
Bandwidth Settings)
Path – This will set the voice path to Dynamic or Constant. Dynamic means
that the Branch Office unit uses the available bandwidth when the remote user
goes off-hook. Constant means that the voice path is always reserved.
DTMF (Avaya Only) – The method of sending tones, which correspond to
numbers, pressed on the telephone, across the network. The tones can be
sent as voice (In-band), or as signals (Out-of-band).
Attenuation– Attenuation decreases the signal being sent to the PBX. This
can be adjusted to decrease the amount of echo during calls.
Silence Detection - When enabled, the Extender detects silent periods during
a conversation, and as a result sends no data during these periods. This
dramatically reduces bandwidth usage, so this parameter should be Enabled
(default setting).
Jitter-The amount of delay (in msec) in sending voice packets. Used to
accommodate jitter (or variable delay) in an IP network. If not set properly
voice may sound choppy.
Packet Size-The number of voice windows included within HDLC on an IP
Packet. It generally reduces packet loss and bandwidth needs, but it will cause
some additional delay in voice delivery.
Packet Trace-Used for debug purposes only.
Calculating Jitter and Compression
Calculating the Number of EXTended phones
Using a single ISDN line, you will only be able to extend a maximum of 8 phones using G.729a
compression. If you plan to extend more than 8 phones, then you will need more bandwidth, in
other words another ISDN Line and another set of ISDN TAs.
The Jitter time should be set to a multiple of the Voice Packet Size Time Equivalent. The Voice
Packet Size Time Equivalent is the amount of time, in milliseconds (ms) of the combined voice
packets.
For example, if using G729A (where each voice packet is equivalent to 10 ms of time) and have a
packet size of 2, then the Voice Packet Size Time Equivalent value is 20 ms (2 packets x 10 ms
for a G729A voice packet). We recommended Jitter settings should be multiples of 20 ms.
Minimum Jitter
Using a single ISDN line, you will only be able to extend a maximum of 8 phones using G.729a
compression. If you plan to extend more than 8 phones, then you will need more bandwidth, in
other words another ISDN Line and another set of ISDN TAs.
The Jitter time should be set to a multiple of the Voice Packet Size Time Equivalent. The Voice
Packet Size Time Equivalent is the amount of time, in milliseconds (ms) of the combined voice
packets.
For example, if using G729A (where each voice packet is equivalent to 10 ms of time) and have a
packet size of 2, then the Voice Packet Size Time Equivalent value is 20 ms (2 packets x 10 ms
for a G729A voice packet). We recommended Jitter settings should be multiples of 20 ms.
Minimum Jitter
• IP only: 2 multiples of Voice Packet Size Time Equivalent should be needed
• Sync only: 1 multiple of Voice Packet Size Time Equivalent should be needed
• Sync only: 1 multiple of Voice Packet Size Time Equivalent should be needed